初學者日記

以下代碼為利用插入OnTouchListener，達到以觸控方式移動物件

public class MainActivity extends Activity implements OnTouchListener{
	ImageView imageView1;
    
	Point touch_xy;
	
    private int   tvWidth  = LayoutParams.WRAP_CONTENT;
    private int   tvHeight = LayoutParams.WRAP_CONTENT;


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


	public void initialization(){
    	imageView1 = (ImageView)findViewById(R.id.image1);
    	imageView1.setOnTouchListener(this);
    	
    	touch_xy = new Point();
    }
	
	
    
	@Override
	public boolean onTouch(View v, MotionEvent event) {
		// TODO 自动生成的方法存根
		
		// 以 event.getAction獲得當前觸控事件。ACTION_DOWN為按下，ACTION_MOVE為移動，ACTION_UP為放開
		switch(event.getAction()){
    	case MotionEvent.ACTION_DOWN:
    		Log.i("touch", "down");
    		
    		// 一開始按下去的位置
    		touch_xy.x = (int)event.getRawX()-30;
    		touch_xy.y = (int) event.getRawY()-100;
    		break;
    	case MotionEvent.ACTION_MOVE:
    		// 利用layout佈局重新定義圖片位置
    		v.setLayoutParams( new AbsoluteLayout.LayoutParams( 
    				tvWidth
                    , tvHeight
                    , touch_xy.x
                    , touch_xy.y
                    ));
    		
    		// 移動中再次取得當前觸控按位置
    		touch_xy.x = (int)event.getRawX()-30;
    		touch_xy.y = (int) event.getRawY()-100;
    		break;	
    	case MotionEvent.ACTION_UP:
    		Log.i("touch", "up");
    		break;	
    	}
		return true;
	}