Android Keyboard Events and screen events operating principles and interaction implementation

When customizing views or playing games, we often use keyboard-triggered events and screen-triggered events! Keyboard-triggered events (such as onKeyDown (int keyCode, KeyEvent event) and screen-triggered events (onTouchEvent) in a custom View )) how do I interact with keyboard-triggered events (such as onKeyDown (int keyCode, KeyEvent event) and screen-triggered events (onTouchEvent) in an activity? What is the operating principle? Let's take a look:

1. Screen trigger event: the activity or view in which the control triggers the screen trigger event in the upper layer. If the return value is default or false, the screen trigger event will be passed down one by one! If the returned value is true, it will not be passed down after the action is executed!
2. keyboard-triggered events: This principle is similar to that of screen-triggered events. However, when the control is not set to focus, generally, the buttons on the keyboard trigger events in the activity (for example, onKeyDown (int keyCode, KeyEvent event )).

The following is an example.:
For example, when playing games, we often customize views. We generally like and use the keyboard trigger events and screen trigger events in this view (GameView), but for example: onKeyDown (int keyCode, keyEvent). Generally, when we press the keyboard, the keyboard trigger event in the activity is directly triggered. How can we make it directly trigger the keyboard trigger event (GameView?

Method 1:
Example 1:Copy codeThe Code is as follows: View Code
Package net. loonggg. project;
Import android. app. Activity;
Import android. OS. Bundle;
Import android. view. KeyEvent;
Import android. view. MotionEvent;
Public class MainActivity extends Activity {
Private GameView gameView;
@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
GameView = new GameView (this );
SetContentView (gameView );
}
@ Override
Public boolean onKeyDown (int keyCode, KeyEvent event ){
System. out. println ("MainActivity:" + "keyCode:" + keyCode + "evnet :"
+ Event );
Return super. onKeyDown (keyCode, event );
}
@ Override
Public boolean onTouchEvent (MotionEvent event ){
System. out. println ("MainActivity:" + "event:" + event + "x :"
+ Event. getX () + "y:" + event. getY ());
Return super. onTouchEvent (event );
}
}
Package net. loonggg. project;
Import android. content. Context;
Import android. graphics. Canvas;
Import android. graphics. Color;
Import android. graphics. Paint;
Import android. view. KeyEvent;
Import android. view. MotionEvent;
Import android. view. View;
Public class GameView extends View {
Private Paint paint;
Private int pointX;
Private int pointY;
Public GameView (Context context ){
Super (context );
// Set GameView to get focus
This. setFocusable (true );
Paint = new Paint ();
Paint. setColor (Color. YELLOW );
Thread t = new Thread (new MyThread ());
T. start ();
}
@ Override
Protected void onDraw (Canvas canvas ){
Super. onDraw (canvas );
Canvas. drawCircle (pointX, pointY, 15, paint );
}
Class MyThread implements Runnable {
@ Override
Public void run (){
While (true ){
Try {
Thread. sleep (3000 );
PointY = pointY + 10;
PointX = pointX + 10;
If (startx> 200 ){
Break;
}
} Catch (InterruptedException e ){
E. printStackTrace ();
}
GameView. this. postInvalidate ();
}
}
}
@ Override
Public boolean onKeyDown (int keyCode, KeyEvent event ){
System. out. println ("GameView:" + "keyCode:" + keyCode + "evnet :"
+ Event );
// This event will not be propagated
Return true;
}
@ Override
Public boolean onTouchEvent (MotionEvent event ){
System. out. println ("GameView:" + "event:" + event + "x :"
+ Event. getX () + "y:" + event. getY ());
// This event will not be propagated
Return true;
}
}

Method 2:Copy codeThe Code is as follows: View Code
Package net. loonggg. project;
Import android. app. Activity;
Import android. OS. Bundle;
Import android. view. KeyEvent;
Import android. view. MotionEvent;
Public class MainActivity extends Activity {
Private GameView gameView;
@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
GameView = new GameView (this );
SetContentView (gameView );
}
@ Override
Public boolean onKeyDown (int keyCode, KeyEvent event ){
System. out. println ("MainActivity:" + "keyCode:" + keyCode + "evnet :"
+ Event );
// Pass the event to gameView
GameView. onKeyDown (keyCode, event );
Return super. onKeyDown (keyCode, event );
}
@ Override
Public boolean onTouchEvent (MotionEvent event ){
System. out. println ("MainActivity:" + "event:" + event + "x :"
+ Event. getX () + "y:" + event. getY ());
// Pass the event to gameView
GameView. onTouchEvent (event );
Return super. onTouchEvent (event );
}
}
Package net. loonggg. project;
Import android. content. Context;
Import android. graphics. Canvas;
Import android. graphics. Color;
Import android. graphics. Paint;
Import android. view. KeyEvent;
Import android. view. MotionEvent;
Import android. view. View;
Public class GameView extends View {
Private Paint paint;
Private int pointX;
Private int pointY;
Public GameView (Context context ){
Super (context );
Paint = new Paint ();
Paint. setColor (Color. YELLOW );
Thread t = new Thread (new MyThread ());
T. start ();
}
@ Override
Protected void onDraw (Canvas canvas ){
Super. onDraw (canvas );
Canvas. drawCircle (pointX, pointY, 15, paint );
}
Class MyThread implements Runnable {
@ Override
Public void run (){
While (true ){
Try {
Thread. sleep (3000 );
PointY = pointY + 10;
PointX = pointX + 10;
If (startx> 200 ){
Break;
}
} Catch (InterruptedException e ){
E. printStackTrace ();
}
GameView. this. postInvalidate ();
}
}
}
@ Override
Public boolean onKeyDown (int keyCode, KeyEvent event ){
System. out. println ("GameView:" + "keyCode:" + keyCode + "evnet :"
+ Event );
Return super. onKeyDown (keyCode, event );
}
@ Override
Public boolean onTouchEvent (MotionEvent event ){
System. out. println ("GameView:" + "event:" + event + "x :"
+ Event. getX () + "y:" + event. getY ());
Return super. onTouchEvent (event );
}
}

Here, the second method is recommended because some simulators in the first method cannot be used!
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