Question

我正在创建一个应用程序，使用该应用程序我可以将应用程序内部的图像设置为手机的背景。我是这个领域的新手。我已经到处搜索并尝试修改我的代码，但它不起作用。

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

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <Button
        android:layout_width="0dip"
        android:layout_height="wrap_content"
        android:layout_weight="25"
        android:onClick="gotoPreviousImage"
        android:padding="10dip"
        android:text="&lt;" />

    <Button
        android:layout_width="0dip"
        android:layout_height="wrap_content"
        android:layout_weight="50"
        android:onClick="setAsWallpaper"
        android:padding="10dip"
        android:text="Set as Background" />

    <Button
        android:layout_width="0dip"
        android:layout_height="wrap_content"
        android:layout_weight="25"
        android:onClick="gotoNextImage"
        android:padding="10dip"
        android:text=">" />
</LinearLayout>

我的MainActivity.java文件

package com.blundell.tutorial.ui.phone;

import static com.blundell.tutorial.util.HeavyLifter.FAIL;
import static com.blundell.tutorial.util.HeavyLifter.SUCCESS;

 import java.util.ArrayList;
 import java.util.List;

   import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

import com.blundell.tutorial.R;
import com.blundell.tutorial.util.HeavyLifter;

public class MainActivity extends Activity {

private static final List<Integer> backgrounds = new ArrayList<Integer>();
/** The total number of backgrounds in the list */
private static final int TOTAL_IMAGES;

static {
    backgrounds.add(R.drawable.background1);
    backgrounds.add(R.drawable.background2);
    backgrounds.add(R.drawable.background3);


    TOTAL_IMAGES = (backgrounds.size() - 1);
}
/** the state of what wallpaper is currently being previewed */
private int currentPosition = 0;
/** our image wallpaper preview */
private ImageView backgroundPreview;

private HeavyLifter chuckNorris;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    backgroundPreview = (ImageView) findViewById(R.id.backgroundPreview);
    // Set the default image to be shown to start with
    changePreviewImage(currentPosition);


    chuckNorris = new HeavyLifter(this, chuckFinishedHandler);
}


public void gotoPreviousImage(View v) {
    int positionToMoveTo = currentPosition;
    positionToMoveTo--;
    if(positionToMoveTo < 0){
        positionToMoveTo = TOTAL_IMAGES;
    }
    changePreviewImage(positionToMoveTo);
}

/**
 * Called from XML when the set wallpaper button is pressed
 * Thie retrieves the id of the current image from our list
 * It then asks chuck to set it as a wallpaper!
 * The chuckHandler will be called when this operation is complete
 * @param v
 */
public void setAsWallpaper(View v) {
    int resourceId = backgrounds.get(currentPosition);
    chuckNorris.setResourceAsWallpaper(resourceId);
}

/**
 * Called from XML when the next button is pressed
 * Increment the current state position

 * @param v
 */
public void gotoNextImage(View v) {
    int positionToMoveTo = currentPosition;
    positionToMoveTo++;
    if(currentPosition == TOTAL_IMAGES){
        positionToMoveTo = 0;
    } 

    changePreviewImage(positionToMoveTo);
}

/**
 * Change the currently showing image on the screen
 * This is quite an expensive operation as each time the system

 */
public void changePreviewImage(int pos) {
    currentPosition = pos;
    backgroundPreview.setImageResource(backgrounds.get(pos));
    Log.d("Main", "Current position: "+pos);
}

/**

 */
private Handler chuckFinishedHandler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        switch(msg.what){
        case SUCCESS:
            Toast.makeText(MainActivity.this, "Wallpaper set",      Toast.LENGTH_SHORT).show();
            break;
        case FAIL:
            Toast.makeText(MainActivity.this, "Uh oh, can't do that right now", Toast.LENGTH_SHORT).show();
            break;
        default:
            super.handleMessage(msg);
        }
    }
};

}

My another Heavylifter.java file

package com.blundell.tutorial.util;

import java.io.IOException;

import android.app.WallpaperManager;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
 import android.os.Handler;
 import android.util.Log;

/ ** * 此类使用线程 *此类的替代方法是使用ASyncTask * @author blundell * * / 公共类HeavyLifter {

public static final int SUCCESS = 0;
public static final int FAIL = 1;

private final Context context;
private final Handler callback;
private WallpaperManager manager;

/**
 * Setup the HeavyLifter
 * @param context the context we are running in - typically an activity
 * @param callback the handler you want to be notified when we finish doing an operation
 */
public HeavyLifter(Context context, Handler callback) {
    this.context = context;
    this.callback = callback;
    this.manager = (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE);
}

/**
 * Takes a resource id of a file within our /res/drawable/ folder<br/>
 * It then spawns a new thread to do its work on<br/>
 * The reource is decoded and converted to a byte array<br/>
 * This array is passed to the system which can use it to set the phones wallpaper<br/>
 * Upon completion the callback handler is sent a message with eith {@link HeavyLifter#SUCCESS} or {@link HeavyLifter#FAIL}
 * 
 * @param resourceId id of a file within our /res/drawable/ folder
 */
public void setResourceAsWallpaper(final int resourceId) {
    new Thread() {
        @Override
        public void run() {
            try {
                manager.setBitmap(getImage(resourceId));
                callback.sendEmptyMessage(SUCCESS);
            } catch (IOException e) {
                Log.e("Main", "Cant set wallpaper");
                callback.sendEmptyMessage(FAIL);
            }
        }
    }.start();
}

/**
 * Decodes a resource into a bitmap, here it uses the convenience method 'BitmapFactory.decodeResource', but you can decode
 * using alternatives these will give you more control over the size and quality of the resource.
 * You may need certain size resources within each of your /hdpi/ /mdpi/ /ldpi/ folders in order
 * to have the quality and look you want on each different phone.
 */
private Bitmap getImage(int resourceId) {
    Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, null);
    Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, manager.getDesiredMinimumWidth(), manager.getDesiredMinimumHeight(), true);
    bitmap.recycle();
    bitmap = null;
    return scaledBitmap;
}

}

壁纸在Android的背景中伸展

0 个答案: