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谷歌如何缩放谷歌地图中的图像，我正在尝试创建一个使用自定义地图而不是谷歌地图的应用程序。一切都很好，只是我无法为尺寸> 240 x 320的手机相应地缩放图像，但对于尺寸大于此的手机会崩溃，因为我超过了android中应用程序的默认堆大小并获得了java .lang.OutOfMemoryError：位图大小超出 VM 预算。我只是不知道如何根据手机的分辨率缩放图像。

这就是正在做的事情：

1）首先计算手机的宽度和高度：

Display display = getWindowManager().getDefaultDisplay();
            Constatnts.SCR_WD = display.getWidth();
            Constatnts.SCR_HT = display.getHeight();

2) 我为 zoomIn 按钮设置了一个 onclicklistener，它调用了 zoomout 函数：

public void zoomOut() {
        if (isloading > 5)
            return;
        System.gc();

        if (zoomLevel < 12) {
            dc = true;
            sc = true;
            emptyBuffer();
            zoom = -1;
            stopload = true;
            bitmapArr1 = new Bitmap[tilesyno][tilesxno];
            for (int i = 0; i < bitmapArr.length; i++) {// row
                for (int j = 0; j < bitmapArr[i].length; j++) {// coloum
                    if (bitmapArr[i][j] != null) {
                        int tmpTilewd = bitmapArr[i][j].getWidth() / 2;
                        int tmpTileHt = bitmapArr[i][j].getHeight() / 2;
                        Bitmap b = ExtraFunctions.ScaleBitmap(bitmapArr[i][j],
                                tmpTilewd, tmpTileHt);
                        if (bitmapArr1 != null)
                            bitmapArr1[i][j] = b;
                    }
                }
            }

            lastPressed1 = System.currentTimeMillis();
            setCenterLatLon();
            zoomLevel++;
            if (!isStarted)
                tryLoadMap();
        }
    }


void tryLoadMap() {
        if (isStarted)
            return;
        isStarted = true;
        Thread th = new Thread() {
            public void run() {
                try {
                    Thread.sleep(System.currentTimeMillis() - lastPressed1);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                loadLocalMap();
                if (showDirection)
                    DirectionPath(lat, lon);

                if (isSearchAvail)
                    SearchPath(lat, lon, tmpselected);

                isStarted = false;
            }
        };
        th.start();
    }

对于缩放：

        public static Bitmap ScaleBitmap(Bitmap bitmapOrg,int newWidth,int newHeight) {
    if(bitmapOrg==null)
        return null;

    int width = bitmapOrg.getWidth();
    int height = bitmapOrg.getHeight();
    // calculate the scale - in this case = 0.4f
    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;

    // createa matrix for the manipulation
    Matrix matrix = new Matrix();
    // resize the bit map
    matrix.postScale(scaleWidth, scaleHeight);
    // rotate the Bitmap
    //matrix.postRotate(45);

    // recreate the new Bitmap
    return Bitmap
            .createBitmap(bitmapOrg, 0, 0, width, height, matrix, true);
}

日志猫：

08-30 17:09:30.342: E/dalvikvm-heap(440): 1451808-byte external allocation too large for this process.
08-30 17:09:30.382: E/GraphicsJNI(440): VM won't let us allocate 1451808 bytes
08-30 17:09:30.382: D/AndroidRuntime(440): Shutting down VM
08-30 17:09:30.401: W/dalvikvm(440): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
08-30 17:09:30.442: E/AndroidRuntime(440): FATAL EXCEPTION: main
08-30 17:09:30.442: E/AndroidRuntime(440): java.lang.IllegalStateException: Could not execute method of the activity
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.view.View$1.onClick(View.java:2072)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.view.View.performClick(View.java:2408)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.view.View$PerformClick.run(View.java:8816)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.os.Handler.handleCallback(Handler.java:587)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.os.Handler.dispatchMessage(Handler.java:92)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.os.Looper.loop(Looper.java:123)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.app.ActivityThread.main(ActivityThread.java:4627)
08-30 17:09:30.442: E/AndroidRuntime(440):  at java.lang.reflect.Method.invokeNative(Native Method)
08-30 17:09:30.442: E/AndroidRuntime(440):  at java.lang.reflect.Method.invoke(Method.java:521)
08-30 17:09:30.442: E/AndroidRuntime(440):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-30 17:09:30.442: E/AndroidRuntime(440):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-30 17:09:30.442: E/AndroidRuntime(440):  at dalvik.system.NativeStart.main(Native Method)
08-30 17:09:30.442: E/AndroidRuntime(440): Caused by: java.lang.reflect.InvocationTargetException
08-30 17:09:30.442: E/AndroidRuntime(440):  at com.Map.zoomIn(MapScreen.java:762)
08-30 17:09:30.442: E/AndroidRuntime(440):  at java.lang.reflect.Method.invokeNative(Native Method)
08-30 17:09:30.442: E/AndroidRuntime(440):  at java.lang.reflect.Method.invoke(Method.java:521)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.view.View$1.onClick(View.java:2067)
08-30 17:09:30.442: E/AndroidRuntime(440):  ... 11 more
08-30 17:09:30.442: E/AndroidRuntime(440): Caused by: java.lang.OutOfMemoryError: bitmap size exceeds VM budget
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.graphics.Bitmap.nativeCreate(Native Method)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.graphics.Bitmap.createBitmap(Bitmap.java:468)
08-30 17:09:30.442: E/AndroidRuntime(440):  at android.graphics.Bitmap.createBitmap(Bitmap.java:435)
08-30 17:09:30.442: E/AndroidRuntime(440):  at com.Map.ncore.XtraFunctions.ScaleBitmap(ExtraFunctions.java:32)
08-30 17:09:30.442: E/AndroidRuntime(440):  at com.Map.MapCanvas.zoomIn(MapCanvas.java:1018)
08-30 17:09:30.442: E/AndroidRuntime(440):  ... 15 more
08-30 17:14:30.522: I/Process(440): Sending signal. PID: 440 SIG: 9
4

1 回答 1

1

嗯是什么bitmapArr[i][j]？那些解码的位图？如果是这样，那么您有点错过了重点。在将它们读入bitmapArr. 否则，您将保留原件和下采样的副本，什么都不保存（实际上使用更多内存）。在知道要缩小到什么大小之前，您不应该从磁盘（或任何地方）读取图像。

于 2012-08-30T12:22:00.303 回答