BlockCanary原理分析

dependencies {    // most often used way, enable notification to notify block event    implementation 'com.github.markzhai:blockcanary-android:1.5.0'
    // this way you only enable BlockCanary in debug package    // debugImplementation 'com.github.markzhai:blockcanary-android:1.5.0'    // releaseImplementation 'com.github.markzhai:blockcanary-no-op:1.5.0'}

public class DemoApplication extends Application {    @Override    public void onCreate() {        // ...        // Do it on main process        BlockCanary.install(this, new BlockCanaryContext()).start();    }}

public static void loop() {    // ....
    for (;;) {        // ...
        // This must be in a local variable, in case a UI event sets the logger        final Printer logging = me.mLogging;        if (logging != null) {            logging.println(">>>>> Dispatching to " + msg.target + " " +                            msg.callback + ": " + msg.what);        }
        // ...        msg.target.dispatchMessage(msg);        // ...
        if (logging != null) {            logging.println("<<<<< Finished to " + msg.target + " " + msg.callback);        }       // ...    }}

Looper mainLooper = Looper.getMainLooper();

...@Overridepublic void println(String x) {    if (!mStartedPrinting) {        mStartTimeMillis = System.currentTimeMillis();        mStartThreadTimeMillis = SystemClock.currentThreadTimeMillis();        mStartedPrinting = true;    } else {        final long endTime = System.currentTimeMillis();        mStartedPrinting = false;        if (isBlock(endTime)) {            notifyBlockEvent(endTime);        }    }}
private boolean isBlock(long endTime) {    return endTime - mStartTimeMillis > mBlockThresholdMillis;}...

Looper.getMainLooper().setMessageLogging(mainLooperPrinter);