带开关功能的ViewPager

1. 需求：
一个ViewPager，正常情况下能滑动，但在某些情况下禁止滑动

2. 分析：
有时候能滑动有时候不能滑动，那最好就是给这个ViewPager做个开关

3. 实现依据：
滑动事件监听函数onTouchEvent，禁止ViewPager滑动，可以在这个方法里不去调用ViewPager实现的滑动。

@Override
	public boolean onTouchEvent(MotionEvent arg0) {
		super.onTouchEvent(arg0);
	}

4. 实现方法:

1. 继承ViewPager，增加一个设置开关的方法来控制MyViewPager里的全局变量

private boolean mEnable = true;
	@Override
	public boolean onTouchEvent(MotionEvent arg0) {
		Log.v(TAG, "onTouchEvent");
		if(!mEnable){
			return true;
		}
		return super.onTouchEvent(arg0);
	}

	public void setViewPageEnable(boolean enable){
		Log.v(TAG, "setViewPageEnable " + enable);
		mEnable = enable;
	}

2. 在适当的时候去关闭/打开这个开关

mPageSwtich.setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				mPagerEnabled = !mPagerEnabled;
				mPager.setViewPageEnable(mPagerEnabled);
				
			}
		});

5. 示例：
src/com/yeezone/viewpage/HelloViewPageActivity.java

package com.yeezone.viewpage;

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class HelloViewPageActivity extends Activity {
    /** Called when the activity is first created. */
    private Button mPageSwtich;
    private boolean mPagerEnabled = true;
    MyViewPager mPager;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mPageSwtich = (Button) findViewById(R.id.viewpage_swtich);
        
        List<View> views = new ArrayList<View>();
        LayoutInflater mLi = LayoutInflater.from(this);
        View view1 = mLi.inflate(R.layout.view1, null);
        ImageView pic = new ImageView(this);
        pic.setImageResource(R.drawable.ic_launcher);
        TextView page3 = new TextView(this);
        page3.setText("Page3");
        View view4 = mLi.inflate(R.layout.view4, null);
        views.add(view1);
        views.add(pic); 
        views.add(page3);
        views.add(view4);
        mPager = (MyViewPager)findViewById(R.id.viewpager);
        mPager.setAdapter(new MyPagerAdapter(views));
        mPageSwtich.setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				mPagerEnabled = !mPagerEnabled;
				mPager.setViewPageEnable(mPagerEnabled);
			}
		});
    }
}

res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/viewpage_swtich"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="PageSwtich" />
    
    <com.yeezone.viewpage.MyViewPager
        android:layout_height="fill_parent"
        android:layout_width="fill_parent"
        android:id="@+id/viewpager"/>
</LinearLayout>

res/layout/view1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="aaa" />
</LinearLayout>

res/layout/view4.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="ddd" />
</LinearLayout>

src/com/yeezone/viewpage/MyViewPager.java

package com.yeezone.viewpage;

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;

public class MyViewPager extends ViewPager{
	private static final String TAG = "MyViewPager";
	private boolean mEnable = true;
	
	public MyViewPager(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
	}


	public MyViewPager(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}

	@Override
	public boolean onTouchEvent(MotionEvent arg0) {
		Log.v(TAG, "onTouchEvent");
		if(!mEnable){
			return true;
		}
		return super.onTouchEvent(arg0);
	}


	public void setViewPageEnable(boolean enable){
		Log.v(TAG, "setViewPageEnable " + enable);
		mEnable = enable;
	}
}

src/com/yeezone/viewpage/MyPagerAdapter.java

package com.yeezone.viewpage;

import java.util.List;
import android.support.v4.view.PagerAdapter;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;

public class MyPagerAdapter extends PagerAdapter{
    private static final String TAG = "MyPagerAdapter";
    private List<View> views;
    
    public MyPagerAdapter(List<View> views) {
        super();
        this.views = views;
    }

    @Override
    public int getCount() {
        Log.v(TAG, "getCount");
        return views.size();
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        Log.v(TAG, "isViewFromObject");
        return arg0==arg1;
    }
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Log.v(TAG, "instantiateItem position = " + position);
        container.addView(views.get(position));
        return views.get(position);
    }
    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        Log.v(TAG, "destroyItem position = " + position);
        container.removeView(views.get(position));
    }
}