<!--波紋視圖-->
<me.chunyu.spike.wcl_visualizer_demo.visualizers.WaveformView
android:id="@+id/main_wv_waveform"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

效果

2. 首頁邏輯

添加動態(tài)權限管理, 在啟動頁面時, 獲取應用所需的音頻權限.
RendererFactory工廠類創(chuàng)建波紋的繪制類SimpleWaveformRender.
startVisualiser方法獲取當前播放音樂的音頻信息.
注意頁面關閉, 在onPause時, 釋放Visualiser類.

public class MainActivity extends AppCompatActivity {
private static final int CAPTURE_SIZE = 256; // 獲取這些數據, 用于顯示
private static final int REQUEST_CODE = 0;
// 權限
private static final String[] PERMISSIONS = new String[]{
Manifest.permission.RECORD_AUDIO,
Manifest.permission.MODIFY_AUDIO_SETTINGS
};
@Bind(R.id.main_wv_waveform) WaveformView mWvWaveform; // 波紋視圖
private Visualizer mVisualizer; // 音頻可視化類
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.bind(this);
RendererFactory rendererFactory = new RendererFactory();
mWvWaveform.setRenderer(rendererFactory.createSimpleWaveformRender(ContextCompat.getColor(this, R.color.colorPrimary), Color.WHITE));
}
@Override protected void onResume() {
super.onResume();
PermissionsChecker checker = new PermissionsChecker(this);

if (checker.lakesPermissions(PERMISSIONS)) {
PermissionsActivity.startActivityForResult(this, REQUEST_CODE, PERMISSIONS);
} else {
startVisualiser();
}
}
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE && resultCode == PermissionsActivity.PERMISSIONS_DENIED) {
finish();
}
}
// 設置音頻線
private void startVisualiser() {
mVisualizer = new Visualizer(0); // 初始化
mVisualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {
@Override
public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform, int samplingRate) {
if (mWvWaveform != null) {
mWvWaveform.setWaveform(waveform);
}
}
@Override
public void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate) {
}
}, Visualizer.getMaxCaptureRate(), true, false);
mVisualizer.setCaptureSize(CAPTURE_SIZE);
mVisualizer.setEnabled(true);
}
// 釋放
@Override protected void onPause() {
if (mVisualizer != null) {
mVisualizer.setEnabled(false);
mVisualizer.release();
}
super.onPause();
}
}

Visualizer類

new Visualizer(0), 初始化; setCaptureSize, 獲取波紋數量; setEnabled, 啟動監(jiān)聽;
setDataCaptureListener, 第一個參數是回調, 使用WaveFormData或FftData; 第二個是更新率; 第三個是判斷使用WaveFormData; 第四個是判斷使用FftData, 第三\四個均與回調的返回值有關.

3. 波紋視圖

頁面框架, 分離顯示和邏輯, 使用接口渲染, 輸入畫布Canvas和波紋Waveform.

/**
* 音頻波紋視圖
* <p>
* Created by wangchenlong on 16/2/11.
*/
public class WaveformView extends View {
private WaveformRenderer mRenderer; // 繪制類
private byte[] mWaveform; // 波紋形狀
public WaveformView(Context context) {
super(context);
}
public WaveformView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public WaveformView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@TargetApi(21)
public WaveformView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
public void setRenderer(WaveformRenderer renderer) {
mRenderer = renderer;
}
public void setWaveform(byte[] waveform) {
mWaveform = Arrays.copyOf(waveform, waveform.length); // 數組復制
invalidate(); // 設置波紋之后, 需要重繪
}
@Override protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mRenderer != null) {
mRenderer.render(canvas, mWaveform);
}
}
}

數組復制Arrays.copyOf(), 在設置波紋后重繪頁面invalidate().

4. 波紋邏輯

核心部分renderWaveform, 渲染波紋.
把頁面分為網格樣式, 根據波紋值, 繪制曲線; 沒有波紋, 繪制居中水平直線.

/**
* 波紋渲染邏輯
* <p>
* Created by wangchenlong on 16/2/12.
*/
public class SimpleWaveformRenderer implements WaveformRenderer {
private static final int Y_FACTOR = 0xFF; // 2的8次方 = 256
private static final float HALF_FACTOR = 0.5f;
@ColorInt private final int mBackgroundColor;
private final Paint mForegroundPaint;
private final Path mWaveformPath;
private SimpleWaveformRenderer(@ColorInt int backgroundColor, Paint foregroundPaint, Path waveformPath) {
mBackgroundColor = backgroundColor;
mForegroundPaint = foregroundPaint;
mWaveformPath = waveformPath;
}
public static SimpleWaveformRenderer newInstance(@ColorInt int backgroundColor, @ColorInt int foregroundColour) {
Paint paint = new Paint();
paint.setColor(foregroundColour);
paint.setAntiAlias(true); // 抗鋸齒
paint.setStrokeWidth(8.0f); // 設置寬度
paint.setStyle(Paint.Style.STROKE); // 填充
Path waveformPath = new Path();
return new SimpleWaveformRenderer(backgroundColor, paint, waveformPath);
}
@Override public void render(Canvas canvas, byte[] waveform) {
canvas.drawColor(mBackgroundColor);
float width = canvas.getWidth();
float height = canvas.getHeight();
mWaveformPath.reset();
// 沒有數據
if (waveform != null) {
// 繪制波形
renderWaveform(waveform, width, height);
} else {
// 繪制直線
renderBlank(width, height);
}
canvas.drawPath(mWaveformPath, mForegroundPaint);
}
private void renderWaveform(byte[] waveform, float width, float height) {
float xIncrement = width / (float) (waveform.length); // 水平塊數
float yIncrement = height / Y_FACTOR; // 豎直塊數
int halfHeight = (int) (height * HALF_FACTOR); // 居中位置
mWaveformPath.moveTo(0, halfHeight);
for (int i = 1; i < waveform.length; ++i) {
float yPosition = waveform[i] > 0 ?
height - (yIncrement * waveform[i]) : -(yIncrement * waveform[i]);
mWaveformPath.lineTo(xIncrement * i, yPosition);
}
mWaveformPath.lineTo(width, halfHeight); // 最后的點, 水平居中
}
// 居中畫一條直線
private void renderBlank(float width, float height) {
int y = (int) (height * HALF_FACTOR);
mWaveformPath.moveTo(0, y);
mWaveformPath.lineTo(width, y);
}
}

繪制移動moveTo, 繪制直線lineTo.

動畫效果