AndroidでViewコンポーネントを更新

invalidate()     View ，    UI       。       view    ，  invalidate()           。invalidate()          view  UI     pop 。   Android               ，               。        ，        UI     、            UI  ，  onCreate()    UI     ，      UI        。               。
invalidate()  UI      ，           Handler   UI        。
 postInvalidate()          

 

 、 Handler.post(Runnable r)  ,Runnable   UI    ,        View.invalidate()

 

Java        

    <span style="">package com.ray.test;  
      
    import android.app.Activity;  
    import android.content.Context;  
    import android.graphics.Canvas;  
    import android.graphics.Color;  
    import android.graphics.Paint;  
    import android.os.Bundle;  
    import android.os.Handler;  
    import android.view.View;  
      
    public class TestHandler extends Activity {  
        private MyView myView;  
        private Handler mHandler;  
        public void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            myView = new MyView(this);  
            mHandler = new Handler();  
            mHandler.post(new Runnable(){  
                @Override  
                public void run() {  
                    myView.invalidate();  //  Handler.post(Runnable    r)  ,Runnable   UI    ,        View.invalidate()  
                    mHandler.postDelayed(this, 5);  
                }  
             });  
            setContentView(myView);  
        }  
          
        class MyView extends View{  
            private float x = 0f;  
            public MyView(Context context) {  
                super(context);  
                  
        }  
            protected void onDraw(Canvas canvas) {  
                super.onDraw(canvas);  
                x+=1;  
                Paint mPaint = new Paint();  
                mPaint.setColor(Color.BLUE);  
                canvas.drawRect(x, 40, x+40, 80, mPaint);  
            }  
              
        }  
    }</span>  

  、       UI,    postInvalidate() .

 
Java        

    public void onCreate(Bundle savedInstanceState) {      
                   super.onCreate(savedInstanceState);      
                   this.requestWindowFeature(Window.FEATURE_NO_TITLE);      
         
                   myView = new MyView(this);  
           this.setContentView(this.myView);      
           new Thread(new myThread()).start();     
    }      
        
        class myThread implements Runnable {      
              public void run() {     
                  while (!Thread.currentThread().isInterrupted()) {      
                       try {  
                              myView.postInvalidate(); // <span style="">       UI,    postInvalidate() .</span>  
                            Thread.sleep(100);       
                       } catch (InterruptedException e) {      
                            Thread.currentThread().interrupt();      
                       }      
                   }      
              }      
        }