Android Touch 簡易觸控

在 Android 中可以藉由 onTouchEvent 事件,

來實現 Touch 觸控功能,

程式範例如下 :

 程式碼

public class helloWorld extends Activity {
    
    private float touchX;
    private float touchY;
    private int   tvWidth  = LayoutParams.WRAP_CONTENT;
    private int   tvHeight = LayoutParams.WRAP_CONTENT;
    private TextView tv = null;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        // 取得 TextView 物件
        tv = (TextView)findViewById(R.id.textWidget);
        tv.setTextColor(0xffffff00);
    }
    
    @Override
    // 利用 MotionEvent 處理觸控程序
    public boolean onTouchEvent(MotionEvent event) {
     
        touchX = event.getX();       // 觸控的 X 軸位置
        touchY = event.getY() - 50;  // 觸控的 Y 軸位置
     
        // 判斷觸控動作
        switch( event.getAction() ) {
      
            case MotionEvent.ACTION_DOWN:  // 按下
       
                // 設定 TextView 內容, 大小, 位置
                tv.setText("X: " + touchX + ", Y: " + touchY + ", 按下");
                tv.setLayoutParams( new AbsoluteLayout.LayoutParams( tvWidth
                                                    , tvHeight
                                                    , (int)touchX
                                                    , (int)touchY
                                                    ));
                break;
                
            case MotionEvent.ACTION_MOVE:  // 拖曳移動
       
                // 設定 TextView 內容, 大小, 位置
                tv.setText("X: " + touchX + ", Y: " + touchY + ", 拖曳移動");
                tv.setLayoutParams( new AbsoluteLayout.LayoutParams( tvWidth
                                     , tvHeight
                                     , (int)touchX
                                     , (int)touchY
                                     ));
                break;
                
            case MotionEvent.ACTION_UP:  // 放開
       
                // 設定 TextView 內容
                tv.setText("X: " + touchX + ", Y: " + touchY + ", 放開");
                break;
        }
     
        // TODO Auto-generated method stub
        return super.onTouchEvent(event);
 }
}

範例結果 :