Android LoaderManager AsyncTaskLoader cancelLoad不deliverResult,Java
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.loader.app.LoaderManager;
import androidx.loader.content.AsyncTaskLoader;
import androidx.loader.content.Loader;
import android.content.Context;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
import android.view.View;
public class MainActivity extends AppCompatActivity {
private static String TAG = "fly";
private LoaderManager loaderManager;
private static int index = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.start).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
index++;
Log.d("fly", "--" + index + "--");
Log.d("fly", "开始新任务" + index);
loaderManager.getLoader(2023).forceLoad();
}
});
findViewById(R.id.cancel).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d("fly", "放弃加载" + index);
loaderManager.getLoader(2023).cancelLoad(); //deliverResult不执行
}
});
setupLoader();
}
private void setupLoader() {
loaderManager = LoaderManager.getInstance(this);
loaderManager.initLoader(2023, new Bundle(), loaderCallbacks);
}
private LoaderManager.LoaderCallbacks loaderCallbacks = new LoaderManager.LoaderCallbacks<String>() {
@NonNull
@Override
public MyTask onCreateLoader(int id, @Nullable Bundle args) {
Log.d(TAG, "onCreateLoader- id - " + id);
MyTask loader = new MyTask(getApplicationContext());
return loader;
}
@Override
public void onLoadFinished(@NonNull Loader<String> loader, String data) {
Log.d(TAG, "onLoadFinished- " + loader.getId() + " " + data);
}
@Override
public void onLoaderReset(@NonNull Loader loader) {
}
};
private static class MyTask extends AsyncTaskLoader<String> {
public MyTask(@NonNull Context context) {
super(context);
}
@Nullable
@Override
public String loadInBackground() {
Log.d("fly", index + " loadInBackground 开始@" + Thread.currentThread().getId());
SystemClock.sleep(5000);
Log.d("fly", index + " loadInBackground 结束@" + Thread.currentThread().getId());
return index + "";
}
@Override
public void deliverResult(@Nullable String data) {
super.deliverResult(data);
Log.d("fly", "deliverResult -> " + data + " 结束");
}
@Override
protected void onStopLoading() { //绑定的Activity生命周期自动执行,切入后台
super.onStopLoading();
Log.d("fly", "onStopLoading");
}
@Override
protected void onStartLoading() { //绑定的Activity生命周期自动执行,切入前台
super.onStartLoading();
}
@Override
public void onCanceled(@Nullable String data) {
super.onCanceled(data);
Log.d("fly", "onCanceled @" + Thread.currentThread().getId());
}
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, "---");
Log.d(TAG, "onStart");
}
@Override
protected void onResume() {
super.onResume();
Log.d(TAG, "onResume");
}
@Override
protected void onStop() {
super.onStop();
Log.d(TAG, "onStop");
}
}