android LoaderManager与AsyncTaskLoader,java（1）

android LoaderManager与AsyncTaskLoader,java（1）

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.util.Log;

public class MainActivity extends AppCompatActivity {
    private static String TAG = "fly";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LoaderManager loaderManager = LoaderManager.getInstance(this);
        loaderManager.initLoader(2023, new Bundle(), new LoaderManager.LoaderCallbacks() {
            @NonNull
            @Override
            public MyLoader onCreateLoader(int id, @Nullable Bundle args) {
                Log.d(TAG, "onCreateLoader - id - " + id);
                MyLoader loader = new MyLoader(getApplicationContext());
                Log.d(TAG, "onCreateLoader - getId() - " + loader.getId());
                return loader;
            }

            @Override
            public void onLoadFinished(@NonNull Loader loader, String data) {
                Log.d(TAG, "onLoadFinished - " + loader.getId() + " - " + data);
            }

            @Override
            public void onLoaderReset(@NonNull Loader loader) {

            }
        });

        //loaderManager.getLoader(2023).startLoading(); 不需要调用，自动执行
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.d(TAG, "----------");
        Log.d(TAG, "onStart");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.d(TAG, "onResume");
    }

    private static class MyLoader extends AsyncTaskLoader {
        public MyLoader(@NonNull Context context) {
            super(context);
            Log.d(TAG, "MyLoader - " + getId());
        }

        @Override
        protected void onStartLoading() {
            super.onStartLoading();
            Log.d(TAG, "onStartLoading - " + getId());

            this.forceLoad();//如果没有，则不会触发loadInBackground
        }

        //work thread
        @Nullable
        @Override
        public String loadInBackground() {
            String s = (String) ("fly@" + System.currentTimeMillis());
            return s;
        }

        //UI main thread
        @Override
        public void deliverResult(@Nullable String data) {
            super.deliverResult(data);
            Log.d(TAG, "deliverResult - " + getId() + " " + data);
        }
    }
}

输出：