位图/画布：java.lang.IllegalArgumentException：width和height必须是＆gt; 0

Question

我正在尝试为我已经正常运行的应用程序添加波形视觉效果，该应用程序将录制声音，然后播放。录制/播放代码工作正常，但是当我尝试添加com.pheelicks.app可视化工具并录制我自己的声音时，然后尝试播放它，当我点击我自己的播放按钮时出现崩溃。

在他的可视化应用程序中，他提供了自己的mp3声音文件，通过MediaPlayer播放。但由于我也通过MediaPlayer播放录制的声音，我认为应该很容易调整我的代码以包含他的可视化器部分。但是出了点问题。

奇怪的是，他的代码在我的Android手机（三星Galaxy 5）中完美运行，我可以看到音乐的可视化器。

我试图研究类似的问题，但我在那里找不到答案。我尝试了this和this这两个类似的错误，但我没有找到解决方案。

错误似乎来自他的代码，位图部分中的 VisualizerView.java ，其中getWidth()和getHeight()来自Canvas onDraw()方法。我还尝试记录这些值，但它们没有显示在我的LogCat中。我正在使用Android Studio。谢谢你的帮助！

编辑：

啊，我看到我的Log声明不起作用，因为它是在崩溃之后放置的。我把它放在崩溃点之前：

if (mCanvasBitmap == null) {
        mCanvasBitmap = Bitmap.createBitmap(canvas.getWidth(),
                canvas.getHeight(), Config.ARGB_8888);
    }

我从LogCat得到了这个：Value of getWidth is 924 and value of getHeight is 0。所以问题是，为什么高度为零？

VisualizerView.java

package org.azurespot.waveform;

/**
 * Created by mizu on 2/2/15.
 */
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import android.util.AttributeSet;
import android.view.View;

import java.util.HashSet;
import java.util.Set;

import static android.util.Log.d;

/**
 * A class that draws visualizations of data received from a
 * {@link Visualizer.OnDataCaptureListener#onWaveFormDataCapture } and
 * {@link Visualizer.OnDataCaptureListener#onFftDataCapture }
 */
public class VisualizerView extends View {
    private static final String TAG = "VisualizerView";

    private byte[] mBytes;
    private byte[] mFFTBytes;
    private Rect mRect = new Rect();
    private Visualizer mVisualizer;

    private Set<Renderer> mRenderers;

    private Paint mFlashPaint = new Paint();
    private Paint mFadePaint = new Paint();

    public VisualizerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs);
        init();
    }

    public VisualizerView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public VisualizerView(Context context) {
        this(context, null, 0);
    }

    private void init() {
        mBytes = null;
        mFFTBytes = null;

        mFlashPaint.setColor(Color.argb(122, 255, 255, 255));
        mFadePaint.setColor(Color.argb(238, 255, 255, 255)); // Adjust alpha to change how quickly the image fades
        mFadePaint.setXfermode(new PorterDuffXfermode(Mode.MULTIPLY));

        mRenderers = new HashSet<Renderer>();
    }

    /**
     * Links the visualizer to a player
     *
     * @param player - MediaPlayer instance to link to
     */
    public void link(MediaPlayer player) {
        if (player == null) {
            throw new NullPointerException("Cannot link to null MediaPlayer");
        }

        // Create the Visualizer object and attach it to our media player.
        mVisualizer = new Visualizer(player.getAudioSessionId());
        mVisualizer.setEnabled(false);
        mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);

        // Pass through Visualizer data to VisualizerView
        Visualizer.OnDataCaptureListener captureListener = new Visualizer.OnDataCaptureListener() {
            @Override
            public void onWaveFormDataCapture(Visualizer visualizer, byte[] bytes,
                                              int samplingRate) {
                updateVisualizer(bytes);
            }

            @Override
            public void onFftDataCapture(Visualizer visualizer, byte[] bytes,
                                         int samplingRate) {
                updateVisualizerFFT(bytes);
            }
        };

        mVisualizer.setDataCaptureListener(captureListener,
                Visualizer.getMaxCaptureRate() / 2, true, true);

        // Enabled Visualizer and disable when we're done with the stream
        mVisualizer.setEnabled(true);
        player.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mediaPlayer) {
                mVisualizer.setEnabled(false);
            }
        });
    }

    public void addRenderer(Renderer renderer) {
        if (renderer != null) {
            mRenderers.add(renderer);
        }
    }

    public void clearRenderers() {
        mRenderers.clear();
    }

    /**
     * Call to release the resources used by VisualizerView. Like with the
     * MediaPlayer it is good practice to call this method
     */
    public void release() {
        mVisualizer.release();
    }

    /**
     * Pass data to the visualizer. Typically this will be obtained from the
     * Android Visualizer.OnDataCaptureListener call back. See
     * {@link Visualizer.OnDataCaptureListener#onWaveFormDataCapture }
     *
     * @param bytes
     */
    public void updateVisualizer(byte[] bytes) {
        mBytes = bytes;
        invalidate();
    }

    /**
     * Pass FFT data to the visualizer. Typically this will be obtained from the
     * Android Visualizer.OnDataCaptureListener call back. See
     * {@link Visualizer.OnDataCaptureListener#onFftDataCapture }
     *
     * @param bytes
     */
    public void updateVisualizerFFT(byte[] bytes) {
        mFFTBytes = bytes;
        invalidate();
    }

    boolean mFlash = false;

    /**
     * Call this to make the visualizer flash. Useful for flashing at the start
     * of a song/loop etc...
     */
    public void flash() {
        mFlash = true;
        invalidate();
    }

    Bitmap mCanvasBitmap;
    Canvas mCanvas;


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        // Create canvas once we're ready to draw
        mRect.set(0, 0, getWidth(), getHeight());

        if (mCanvasBitmap == null) {
            mCanvasBitmap = Bitmap.createBitmap(canvas.getWidth(),
                    canvas.getHeight(), Config.ARGB_8888);
        }

        d("DEBUG", "Value of getWidth is " + canvas.getWidth()
                + " and value of getHeight is " + canvas.getHeight());
        if (mCanvas == null) {
            mCanvas = new Canvas(mCanvasBitmap);
        }

        if (mBytes != null) {
            // Render all audio renderers
            AudioData audioData = new AudioData(mBytes);
            for (Renderer r : mRenderers) {
                r.render(mCanvas, audioData, mRect);
            }
        }

        if (mFFTBytes != null) {
            // Render all FFT renderers
            FFTData fftData = new FFTData(mFFTBytes);
            for (Renderer r : mRenderers) {
                r.render(mCanvas, fftData, mRect);
            }
        }

        // Fade out old contents
        mCanvas.drawPaint(mFadePaint);

        if (mFlash) {
            mFlash = false;
            mCanvas.drawPaint(mFlashPaint);
        }

        canvas.drawBitmap(mCanvasBitmap, new Matrix(), null);
    }
}

logcat的

02-02 22:31:16.699  19125-19125/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: org.azurespot, PID: 19125
    java.lang.IllegalArgumentException: width and height must be > 0
            at android.graphics.Bitmap.createBitmap(Bitmap.java:922)
            at android.graphics.Bitmap.createBitmap(Bitmap.java:901)
            at android.graphics.Bitmap.createBitmap(Bitmap.java:868)
            at org.azurespot.waveform.VisualizerView.onDraw(VisualizerView.java:176)
            at android.view.View.draw(View.java:15393)
            at android.view.View.getDisplayList(View.java:14287)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3284)
            at android.view.View.getDisplayList(View.java:14224)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3284)
            at android.view.View.getDisplayList(View.java:14224)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3284)
            at android.view.View.getDisplayList(View.java:14224)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3284)
            at android.view.View.getDisplayList(View.java:14224)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3284)
            at android.view.View.getDisplayList(View.java:14224)
            at android.view.View.getDisplayList(View.java:14329)
            at android.view.HardwareRenderer$GlRenderer.buildDisplayList(HardwareRenderer.java:1576)
            at android.view.HardwareRenderer$GlRenderer.draw(HardwareRenderer.java:1455)
            at android.view.ViewRootImpl.draw(ViewRootImpl.java:2754)
            at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2620)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2188)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1249)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6585)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:803)
            at android.view.Choreographer.doCallbacks(Choreographer.java:603)
            at android.view.Choreographer.doFrame(Choreographer.java:573)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:789)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5579)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

原来我的xml中包含FrameLayout小部件的VisualizerView是罪魁祸首！代码来自com.pheelicks.app，因此我没有想到任何内容，因为我已经看到FrameLayout在0dp之前显示此类型的大小（在片段中）。但是，奇怪的是，我决定让它更大，并且可视化器确实出现了。它是这些小东西的惊人之处。不遗余力！下面是我的xml中的小部件，我将高度更改为200dp（来自0dp）并修复了它。

<强> activity_make_sounds.xml

<FrameLayout
    android:layout_width="fill_parent"
    android:layout_height="200dp"
    android:layout_margin="10dp"
    android:background="#000" >

    <org.azurespot.waveform.VisualizerView
        android:id="@+id/visualizerView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </org.azurespot.waveform.VisualizerView>

</FrameLayout>