UI卡顿优化blockcanary
项目越来越复杂，代码复杂度也越来越深。如果出现了UI卡顿，很难定位到是哪里的问题。 一个Activity可能包括了很多页面很多回调，怎么找到这些卡顿的元凶呢？ BlockCanary是一个非侵入的性能监控组件，解决UI卡顿
UI卡顿原理
1，60fps / 16ms/帧
2，尽量在16ms内处理完所有的CPU也Gpu计算、绘制、渲染等操作。否则会UI卡顿
UI卡顿常见原因
1，UI线程做了耗时操作。
2，Layout过于复杂，无法在16ms完成
3，View过度绘制
4，View频繁触发measure、layout
5，内存频繁触发GC。内存频繁创建变量
BlockCanary简单使用
1，gradle引入依赖
implementation 'com.github.markzhai:blockcanary-android:1.5.0'
1，Application中注册
BlockCanary.install(this, BlockCanaryContext.get()).start();
BlockCanary原理
android在ActivityThread的main方法定了了mainLooper
在handler.dispatchMessage方法前后计算出时间差，如果超过了阈值，就是dump出堆栈信息、cpu信息、内存信息。
通过往Looper.getMainLooper().setMessageLogging插入一个回调实现的
1，注册、初始化
BlockCanary.install(）
BlockCanary{
public static BlockCanary install(Context context, BlockCanaryContext blockCanaryContext) {
BlockCanaryContext.init(context, blockCanaryContext);
setEnabled(context, DisplayActivity.class, BlockCanaryContext.get().displayNotification());
return get();
}
//get()方法调用到构造方法
private static BlockCanary sInstance;
private BlockCanaryInternals mBlockCanaryCore;
private boolean mMonitorStarted = false;
private BlockCanary() {
BlockCanaryInternals.setContext(BlockCanaryContext.get());
mBlockCanaryCore = BlockCanaryInternals.getInstance();
mBlockCanaryCore.addBlockInterceptor(BlockCanaryContext.get());
if (!BlockCanaryContext.get().displayNotification()) {
return;
}
mBlockCanaryCore.addBlockInterceptor(new DisplayService());
}
}
public final class BlockCanaryInternals {
LooperMonitor monitor;
StackSampler stackSampler;
CpuSampler cpuSampler;
}
2，注册、初始化
BlockCanary.start()
BlockCanary{
public void start() {
if (!mMonitorStarted) {
mMonitorStarted = true;
Looper.getMainLooper().setMessageLogging(mBlockCanaryCore.monitor);
}
}
}
Looper {
public static void loop() {
for (;;) {
...
final Printer logging = me.mLogging;
if (logging != null) {
logging.println(">>>>> Dispatching to " + msg.target + " " +
msg.callback + ": " + msg.what);
}
if (logging != null) {
logging.println("<<<<< Finished to " + msg.target + " " + msg.callback);
}
}
}
LooperMonitor {
@Override
public void println(String x) {
if (mStopWhenDebugging && Debug.isDebuggerConnected()) {
return;
}
if (!mPrintingStarted) {
mStartTimestamp = System.currentTimeMillis();
mStartThreadTimestamp = SystemClock.currentThreadTimeMillis();
mPrintingStarted = true;
startDump();
} else {
final long endTime = System.currentTimeMillis();
mPrintingStarted = false;
if (isBlock(endTime)) {
notifyBlockEvent(endTime);
}
stopDump();
}
}
private boolean isBlock(long endTime) {
return endTime - mStartTimestamp > mBlockThresholdMillis;
}
}
