长按事件的处理

（一）实现效果：长按两秒将图片设置成背景图

1，布局activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="helloworld.com.inspur.demo5.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv_show"
        android:text="点击设置背景"
        />

    <ImageButton
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/im"
        android:src="@drawable/a"
        />



</LinearLayout>

2，MainActivity实现逻辑代码

package helloworld.com.inspur.demo5;

import android.graphics.drawable.Drawable;
import android.nfc.TagLostException;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.graphics.drawable.DrawableWrapper;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private TextView textView;
    private ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //初始化
        textView=(TextView)findViewById(R.id.tv_show);
        imageView=(ImageView)findViewById(R.id.im);
        textView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                imageView.setBackgroundResource(R.drawable.a);
                textView.setText("hahhah");
                return true;
            }
        });
       
    }
}

3，测试public void onClick(View v)中返回值的区别

true：事件已经完全处理，不需要其他的函数继续处理

false：事件未完全处理，还需要继续处理

 textView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                imageView.setBackgroundResource(R.drawable.a);
                textView.setText("hahhah");
                return true;
            }
        });
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
              //  Toast.makeText(MainActivity.this,"hahh",Toast.LENGTH_SHORT);
                textView.setText("111111");
            }
        });

4，改成长按设置成壁纸

（1）设置权限：在application上面加入代码：

  <uses-permission android:name="android.permission.SET_WALLPAPER"/>

（2）编写逻辑代码

textView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                imageView.setBackgroundResource(R.drawable.a);
                setWallPaper();
                textView.setText("hahhah");
                return true;
            }
        });

public void setWallPaper()
    {
        try {
            WallpaperManager wallpaperManager = WallpaperManager.getInstance(MainActivity.this);
            wallpaperManager.setResource(R.drawable.a);
        }
        catch(Exception e)
        {

        }
    }

会报错，但是可以正常运行