我正在开发一个 Android 壁纸应用程序。我正在尝试为 4.0 及更高版本的 Android 设备开发它。但即使我研究了很多，阅读了很多关于不同屏幕尺寸的 scailng 壁纸的信息，我也无法解决这个问题。这是main_activiy：
package com.abcd.iphone5sduvarkagidi;
import static com.abcd.iphone5sduvarkagidi.HeavyLifter.FAIL;
import static com.abcd.iphone5sduvarkagidi.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.abcd.iphone5sduvarkagidi.R;
import com.abcd.iphone5sduvarkagidi.HeavyLifter;
public class MainActivity extends Activity {
/**
* A list containing the resource identifiers for all of our selectable
* backgrounds
*/
private static final List<Integer> backgrounds = new ArrayList<Integer>();
/** The total number of backgrounds in the list */
private static final int TOTAL_IMAGES;
/**
* Instantiate the list statically, so this will be done once on app load,
* also calculate the total number of backgrounds
*/
static {
backgrounds.add(R.drawable.iphone5s_1);
backgrounds.add(R.drawable.iphone5s_big_2_600_1024);
// We -1 as lists are zero indexed (0-2 is a size of 2) - we'll make use
// of this to implement a browsing loop
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;
/**
* A helper class that will do the heavy work of decoding images and
* actually setting the wallpaper
*/
private HeavyLifter chuckNorris;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
backgroundPreview = (ImageView) findViewById(R.id.imageView1);
// Set the default image to be shown to start with
changePreviewImage(currentPosition);
// Load are heavy lifter (goes and does work on another thread), to get
// a response after the lifters thread
// has finished we pass in a Handler that will be notified when it
// completes
chuckNorris = new HeavyLifter(this, chuckFinishedHandler);
}
/**
* Called from XML when the previous button is pressed Decrement the current
* state position If the position is now less than 0 loop round and show the
* last image (the array size)
*
* @param v
*/
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 If the position is now greater than are array size loop
* round and show the first image again
*
* @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 has to decode the image from
* our resources - alternatives are possible (a list of drawables created at
* app start)
*
* @param pos
* the position in {@link MainActivity#backgrounds} to select the
* image from
*/
public void changePreviewImage(int pos) {
currentPosition = pos;
backgroundPreview.setImageResource(backgrounds.get(pos));
Log.d("Main", "Current position: " + pos);
}
/**
* This is the handler that is notified when are HeavyLifter is finished
* doing an operation
*/
private Handler chuckFinishedHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SUCCESS:
Toast.makeText(MainActivity.this, "Duvar kağıdı ayarlandı",
Toast.LENGTH_SHORT).show();
break;
case FAIL:
Toast.makeText(MainActivity.this, "Bir hata oluştu",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
};
}
Here's the Heavy Lifter.java
package com.abcd.iphone5sduvarkagidi;
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;
/**
* <b>This class uses Threads</b>
* An alternative to this class would be to use an ASyncTask
* @author aflazi
*
*/
public class 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 resource 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 {@link HeavyLifter#SUCCESS} or {@link HeavyLifter#FAIL}
*
* @param resourceId id of a file within our /res/drawable/ldpi/mdpi/hdpi/xhdpi 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", "Duvar kağıdı ayarlanamadı");
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.
*/
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;
}
}
我还为小、正常、大和超大屏幕创建了不同的布局。我将不同大小的图像添加到可绘制文件夹中。但是当我尝试在 AVD 中设置壁纸时，壁纸看起来很糟糕，而不是针对设备进行缩放。请帮忙。