安卓开发之——滑动识别

安卓操作当中很重要的一点就是识别点击滑动等操作。这一类操作都有系统提供相应的接口。

我在学习的过程中出现一个问题怎么都解决不了，后来回过头来看，还是没有吧整个安卓的接口函数的逻辑理清楚。以至于我忽略了别人代码中一些没有提及的东西。以致半天解决不了。只要细细想想整个接口调用的逻辑就不会出现这个问题了。

下面直接说滑动操作怎么识别的吧。首先附上XML代码，这部分代码没什么重点，随便怎么写都可以的。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/container"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="hello!"/>
        
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="test"
        />    
        
    
</RelativeLayout>

然后是Activity的代码。

package com.kiplening.timerpick;

import com.kiplening.timerpick.R;

import android.app.Activity;
import android.app.Fragment;
import android.gesture.GestureOverlayView;
import android.gesture.GestureOverlayView.OnGestureListener;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.TimePicker.OnTimeChangedListener;
import android.os.Build;

public class MainActivity extends Activity implements OnTouchListener,OnGestureListener,android.view.GestureDetector.OnGestureListener{
	private TextView textView;
	private Button button;
	private GestureDetector gestureDetector;
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        gestureDetector = new GestureDetector(this);
        RelativeLayout relativeLayout=(RelativeLayout)findViewById(R.id.container);   
        relativeLayout.setOnTouchListener(this);
//        relativeLayout.setOnGestureListener(this);
        relativeLayout.setLongClickable(true);   
        
        textView = (TextView)findViewById(R.id.textView);
        button =(Button)findViewById(R.id.button);
        
        ButtonListener buttonListener = new ButtonListener();
        button.setOnClickListener(buttonListener);
        
        
    }

    
    class ButtonListener implements OnClickListener{

		@Override
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			
			textView.setText("button");
			
		}
    	
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.activity_main, container, false);
            return rootView;
        }
    }


	@Override
	public boolean onDown(MotionEvent arg0) {
		// TODO Auto-generated method stub
		return false;
	}

	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,   
            float velocityY) {
		// TODO Auto-generated method stub
		if (e1.getX()-e2.getX() > 5    
                && Math.abs(velocityX) > 0) {    
            // Fling left    
            System.out.print("left");  
            textView.setText("llllll");
        } else if (e2.getX()-e1.getX() > 5    
                && Math.abs(velocityX) > 0) {    
            // Fling right    
        	textView.setText("rrrrrr");
        }    
		return false;
	}

	@Override
	public void onLongPress(MotionEvent arg0) {
		// TODO Auto-generated method stub
		textView.setText("long");
		System.out.print("test");
	}

	@Override
	public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,
			float arg3) {
		// TODO Auto-generated method stub
		textView.setText("ssssssssss");
		return false;
	}

	@Override
	public void onShowPress(MotionEvent arg0) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public boolean onSingleTapUp(MotionEvent arg0) {
		// TODO Auto-generated method stub
		textView.setText("upupup");
		return false;
	}

	@Override
	public void onGesture(GestureOverlayView overlay, MotionEvent event) {
		// TODO Auto-generated method stub
		textView.setText("gesture");
	}

	@Override
	public void onGestureCancelled(GestureOverlayView overlay, MotionEvent event) {
		// TODO Auto-generated method stub
		textView.setText("call gesture");
	}

	@Override
	public void onGestureEnded(GestureOverlayView overlay, MotionEvent event) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onGestureStarted(GestureOverlayView overlay, MotionEvent event) {
		// TODO Auto-generated method stub
		textView.setText("start");
	}

	@Override
	public boolean onTouch(View v, MotionEvent event) {
		// TODO Auto-generated method stub
		gestureDetector.onTouchEvent(event); 
		return true;
	}

}

 我出现的问题主要出现在，我只想到重写了onFling()方法，没有仔细思考它和OnTouch 之间的关系。我们必须改写Ontouch，在里面要调用

public boolean onTouch(View v, MotionEvent event) {
		// TODO Auto-generated method stub
		gestureDetector.onTouchEvent(event); 
		return true;
	}

这样才能保证你的滑动操作能够被识别。