memory

activity_main.xml

<Button
android:id="@+id/btn01"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="AlertDialog" />

<Button
android:id="@+id/btn02"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="CustomDialog" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tvTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="hahahohohehe"
android:textSize="20dp"/>
<TextView
android:id="@+id/tv01"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="20dp"
android:textStyle="bold"/>
</LinearLayout>

custom.xml

<ImageButton
android:id="@+id/imgBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/sym_def_app_icon"/>
<EditText
android:id="@+id/editText01"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint = "put expected one!!!"/>

MainActivity.java

public class MainActivity extends AppCompatActivity {
Button btn_alert;
Button btn_custom;
TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

btn_alert = findViewById(R.id.btn01);
btn_custom = findViewById(R.id.btn02);
textView = findViewById(R.id.tv01);

btn_alert.setOnClickListener(listener);
btn_custom.setOnClickListener(listener);
}
View.OnClickListener listener = new View.OnClickListener(){
public void onClick(View v){
switch (v.getId()){
case R.id.btn01:
new AlertDialog.Builder(MainActivity.this)
.setTitle("aabbccddeefff")
.setMessage("12312312313")
.setIcon(android.R.drawable.ic_dialog_alert)
.setPositiveButton("YES", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
Toast.makeText(getBaseContext(), "YES", Toast.LENGTH_LONG).show();
textView.setText("ILikeEliphant");
}
})
.setNegativeButton("NO", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
Toast.makeText(getBaseContext(), "NO", Toast.LENGTH_LONG).show();
textView.setText("choose again");
}
})
.show();
break;
case R.id.btn02:
LinearLayout linearLayout = (LinearLayout)View.inflate(MainActivity.this, R.layout.custom, null);
final EditText editText = linearLayout.findViewById(R.id.editText01);

new AlertDialog.Builder(MainActivity.this)
.setTitle("hehehehehehehe")
.setView(linearLayout)
.setPositiveButton("OK", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
Toast.makeText(getBaseContext(), "OK", Toast.LENGTH_LONG).show();
String winner = editText.getText().toString();
textView.setText(winner);
}
})
.setNegativeButton("CANCEL", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
Toast.makeText(MainActivity.this, "CANCEL", Toast.LENGTH_LONG).show();
}
})
.show();
break;
}
}
};
}

--alert dialog--

activity_main.xml

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="open alert dialog"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="44dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:text="check"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />

MainActivity.java

public class MainActivity extends AppCompatActivity {
TextView textView;
Button button;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

textView = findViewById(R.id.textView);
button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener(){
public void onClick(View view){
showDialog();
}
});
}
private void showDialog(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);

builder.setTitle("alert");
builder.setMessage("wanna finish?");
builder.setIcon(android.R.drawable.ic_dialog_info);
builder.setPositiveButton("yes", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
String msg = "you have put yes";
textView.setText(msg);
}
});
builder.setNegativeButton("no", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn) {
String msg = "you have put no";
textView.setText(msg);
}
});
builder.setNeutralButton("cancel", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int btn){
String msg = "you have put cancel";
textView.setText(msg);
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
}

--progress bar--

activity_main.xml

<ProgressBar
android:id = "@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:max="100"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<Button
android:id="@+id/btn1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text = "check message"
android:layout_weight="1"/>
<Button
android:id="@+id/btn2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="close"
android:layout_weight="1"/>
</LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
ProgressDialog dialog;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

ProgressBar progressBar = findViewById(R.id.progressBar);
progressBar.setProgress(40);

Button button = findViewById(R.id.btn1);
button.setOnClickListener(new View.OnClickListener(){
public void onClick(View view){
dialog = new ProgressDialog(MainActivity.this);
dialog.setMessage("checking the progress");
dialog.show();
}
});
Button button2 = findViewById(R.id.btn2);
button2.setOnClickListener(new View.OnClickListener(){
public void onClick(View view){
if(dialog != null){
dialog.dismiss();
}
}
});
}
}

Manifest에 configChanges 속성을 설정한후

MainActivity에서 onConfigurationChanged() method를 overriding해준다

//manifests안에 AndroidManifest.xml파일에서 activity tag안에서 configChanges속석을 설정한다

AndroidManifest.xml

<activity android:name=".MainActivity"
android:configChanges="orientation|screenSize|keyboardHidden">
<!--android:screenOrientation = "landscape"
가로상태로 고정되어 변하지 않는다-->
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

activity_main.xml

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="try to change the view direction"
android:textSize="25sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

MainActivity.java

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void onConfigurationChanged(Configuration configuration){
super.onConfigurationChanged(configuration);

if(configuration.orientation == Configuration.ORIENTATION_LANDSCAPE){
displayToast("landscape");
}else if(configuration.orientation == Configuration.ORIENTATION_PORTRAIT){
displayToast("portrait");
}
}
public void displayToast(String message){
Toast.makeText(context: this, message, Toast.LENGTH_LONG).show();
}
}

res/new/android resource directory를 이용해

layout-land를 생성후 그 폴더안에 activity_main.xml을 생성

//가로방향으로 전환될때 사용하는 폴더

//onSaveInstanceState()를 호출하면서 전황시 상태값이 저장된다

activity_main.xml

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="vertical"
android:textSize="30dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

<EditText
android:id="@+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="41dp"
android:layout_marginBottom="29dp"
android:ems="10"
android:hint="text"
android:textSize="24sp"
app:layout_constraintBottom_toTopOf="@+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />

<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="166dp"
android:layout_marginLeft="166dp"
android:layout_marginTop="29dp"
android:layout_marginEnd="157dp"
android:layout_marginRight="157dp"
android:text="check"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editText" />

activity_main.xml

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="horizontal"
android:textSize="30dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

<EditText
android:id="@+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="text"
android:textSize="24sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="242dp" />

<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="check"
tools:layout_editor_absoluteX="344dp"
tools:layout_editor_absoluteY="313dp"/>

MainActivity.java

public class MainActivity extends AppCompatActivity {
String inputText;
EditText editText;
Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
displayToast("onCreate() call");

//상태값 저장
editText = findViewById(R.id.editText);
button = findViewById(R.id.button);

button.setOnClickListener(new View.OnClickListener(){
public void onClick(View view){
inputText= editText.getText().toString();
Toast.makeText(getApplicationContext(), "saved"+inputText, Toast.LENGTH_LONG).show();
} //onClick method를 overriding해준다
});
if(savedInstanceState != null){
inputText = savedInstanceState.getString("inputText");

Toast.makeText(getApplicationContext(), "saved value:" +inputText, Toast.LENGTH_LONG).show();
}
}

protected void onSaveInstanceState(Bundle outState){
super.onSaveInstanceState(outState);

outState.putString("inputText", inputText);
}

// protected void onStart(){
// super.onStart();
// displayToast("onStart() call");
// }
protected void onStop(){
super.onStop();
displayToast("onStart() call");
}
protected void onDestroy(){
super.onDestroy();
displayToast("onDestroy() call");
}

public void displayToast(String message){
Toast.makeText(this, message, Toast.LENGTH_LONG).show();
}
}

activity_main.xml

<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="focus event"
android:textSize="20dp"
android:background="#ff0"
android:gravity="center"
android:padding = "10dp"/>
<EditText
android:id="@+id/editText1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="put id"
android:padding="10dp"
android:background="@drawable/focus_selector"
android:textColorHint = "#ff0"
android:textSize="20dp"/>
<EditText
android:id="@+id/editText2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="put password"
android:padding="10dp"
android:background="@drawable/focus_selector"
android:textColorHint = "#ff0"
android:textSize="20dp"/>

focus_selector.xml

//res\drawable

<item android:state_focused = "true"
android:drawable="@drawable/red"/>
<item android:drawable="@drawable/blue"/>

MainActivity.java

activity_main.xml

<View
android:id="@+id/view1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@android:color/holo_orange_dark"/>
<View
android:id="@+id/view2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@android:color/holo_blue_light"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>

MainActivity.java

public class MainActivity extends AppCompatActivity {
TextView textView;

GestureDetector gestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

textView = findViewById(R.id.textView);

View view = findViewById(R.id.view1);

view.setOnTouchListener(new View.OnTouchListener(){
public boolean onTouch(View view, MotionEvent mE){
int action = mE.getAction();//어떤 action인지 알기위해
float x = mE.getX();
float y = mE.getY();

if(action == MotionEvent.ACTION_DOWN){
output("touched"+ x +", "+y+"\n");
//append는 계속해서 내용을 추가한다
}else if(action == MotionEvent.ACTION_MOVE){
output("moved"+ x +", "+y+"\n");
}else if(action == MotionEvent.ACTION_UP){
output("gone"+ x +", "+y+"\n");
}
return true;
}
});

//getsture event
View view2 = findViewById(R.id.view2);
view2.setOnTouchListener(new View.OnTouchListener(){
public boolean onTouch(View view, MotionEvent mE){
gestureDetector.onTouchEvent(mE);
return true;
}
});
gestureDetector = new GestureDetector(this, new GestureDetector.OnGestureListener(){
public boolean onDown(MotionEvent mE){
output("onDown() call");
return true;
}
//화면에 터치했다가 떨어질때 발생하는 event
public void onShowPress(MotionEvent mE){
output("onShowPress() call");
}
//한손으로 터치했다 떨어지는 event 처리
public boolean onSingleTapUp(MotionEvent mE){
output("onSingleTapUp() call");
return true;
}
//손가락으로 오랫동안 터치하는 event 처리
public void onLongPress(MotionEvent mE){
output("onLongPress() call");
}
//터치된 채 일정한 속도와 방향으로 움직였다 떨어지는 event
public boolean onScroll(MotionEvent mE, MotionEvent mE2, float distanceX, float distanceY){
output("onScroll() call"+distanceX+", "+distanceY);
return true;
}
//터치된채 가속도를 내서 움직였다 떨어지는 event처리
public boolean onFling(MotionEvent mE, MotionEvent mE2, float vX, float vY){
output("onFling() call"+vX+", "+vY);
return true;
}
});
}
public void output(String data){
textView.append(data+"\n");
}
}

activity_main.xml

<Button
android:id="@+id/btn1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="icon change"/>
<Button
android:id="@+id/btn2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="icon change"/>

<com.example.myapplication.Layout01
android:id="@+id/layout01"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>

layout.xml

<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:cardBackgroundColor = "#eeeeee"
app:cardCornerRadius="10dp"
app:cardElevation="5dp"
app:cardUseCompatPadding="true">

<LinearLayout
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content">

<ImageView
android:id="@+id/imageView"
android:layout_width="80dp"
android:layout_height="80dp"
android:padding="10dp"
app:srcCompat="@mipmap/ic_launcher"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="title"
android:textSize = "26sp"/>
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="contents"
android:textColor="#00f"
android:textSize="16sp"/>
</LinearLayout>
</LinearLayout>
</androidx.cardview.widget.CardView>

Layout01.java

public class Layout01 extends LinearLayout {
ImageView imageView;
TextView textView;
TextView textView2;

public Layout01(Context context){
super(context);
init(context);
//생성자가 생성될때 inflation이 같이 되도록 하기위해
}//생성자
public Layout01(Context context, AttributeSet attrs){
super(context, attrs);
init(context);
}//xml속성을 활용하기위해

private void init(Context context){
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.layout, root: this, attachToRoot: true);
imageView = findViewById(R.id.imageView);
textView = findViewById(R.id.textView);
textView2 = findViewById(R.id.textView2);
} //초기화작업을 생성자를 통해 하기위해 init method를 이용한다
public void setImage(int resId){
imageView.setImageResource(resId);
}
public void setTitle(String title){
textView.setText(title);
}
public void setComment(String comment){
textView2.setText(comment);
}
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

Layout01 layout01;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

layout01 = findViewById(R.id.layout01);
layout01.setImage(R.drawable.ic_launcher_foreground);
layout01.setTitle("hahahoho");
layout01.setComment("hihihihi");

Button btn = findViewById(R.id.btn1);
btn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
layout01.setImage(R.drawable.icon);
}
});
Button btn2 = findViewById(R.id.btn2);
btn2.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
layout01.setImage(R.drawable.icon);
}
});
}
}

onDraw()는 view가 화면에 보일때 자동으로 호출되는

method로 재정의를 통해 Button의 style을 지정할수있다

invalidate()는 onDraw() method를 호출하면서 

Button을 이동한 좌표에 지정된 style을 적용할수있다

activity_main.xml

<!--파일 위치를 불러온다-->
<com.example.myapplication.DemoButton
android:id="@+id/btn"
android:layout_width="250dp"
android:layout_height="100dp"
android:text="button style change"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"/>

dimens.xml

//res\values\dimens.xml

<dimen name="text_size">10sp</dimen>
<!--getResources() method를 이용해 Resource 객채를 얻어오고
Resource 객체에 getDimension() method를 이용해 참조할수있다
setTextSize() method를 이용해 float pixel값으로 return받는다 -->

DemoButton.java

public class DemoButton extends AppCompatButton {

//소스코드에서 new연산자를 이용하여 생성하는경우 사용하는 생성자
public DemoButton(Context context){
super(context);

init(context);
} //생성자 생성
//안드로이드 UI 객체를 생성시에는
//반드시 Context를 인자로 사용한다

//view를 xml layout에 추가하는경우 사용하는 생성자
public DemoButton(Context context, AttributeSet attrs){
super(context, attrs);

init(context);
} //생성자 생성
//AttributeSet을통해 xml에 추가된 속성을 전달 받는다

//초기화를 위한 method
private void init(Context context){
setBackgroundColor(Color.CYAN);
setTextColor(Color.GREEN);
//text size 지정
float size = getResources().getDimension(R.dimen.text_size);
setTextSize(size);
}
//view가 화면에 그려질때 자동으로 호출되는 method
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
Log.d("DemoButton", "onDraw()");
//onDraw호출되는 시점을 출력하기위해
}
//view가 터치될때 호출되는 method
public boolean onTouchEvent(MotionEvent event){
Log.d("DemoButton", "onTouchEvent()");
int action = event.getAction();

switch(action){
case MotionEvent.ACTION_DOWN:
setBackgroundColor(Color.GREEN);
setTextColor(Color.MAGENTA);
break;
case MotionEvent.ACTION_OUTSIDE:
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
setBackgroundColor(Color.MAGENTA);
setTextColor(Color.GREEN);
break;
}
invalidate();
//설정된 값으로 다시 그려준다(onDraw() 호출)
return true;
}
}