AsyncTaskLoader使用方法

该文章来自我自己的新博客：AsyncTaskLoader解析

AsyncTaskLoader

 ↳ android.support.v4.content.Loader
      ↳ android.support.v4.content.AsyncTaskLoader

基本用法

创建一个继承于AsyncTaskLoader的自定义Loder类

cancelLoadInBackground

实现以下三个常用方法和一个默认构造函数：

public SycnTasker(@NonNull Context context) {}

@Override
protected void onStartLoading() {}

@Nullable
@Override
public Integer loadInBackground() {}

@Override
protected boolean onCancelLoad() {}

其中默认构造函数和loadInBackground必不可少

onStartLoading

在执行完方法onCreateLoader返回一个自定义Loader对象后开始执行

loadInBackground

当在onStartLoading中调用forceLoad()时开始执行

onCancelLoad

当调用cancleLoad方法时会执行

实现android.support.v4.app.LoaderManager.LoaderCallbacks接口

@Override
public void onLoadFinished(Loader loader, D d) {}

@Override
public Loader onCreateLoader(int i, Bundle bundle) {}

@Override
public void onLoaderReset(Loader loader) {}

onCreateLoader

当调用以下代码后开始执行

getLoaderManager().initLoader(int id,Bundle bundle,LoaderCallbacks loaderCallbacks);

onLoadFinished

执行完成loadInBackground后，数据可从onLoadFinished参数d中获得

onLoaderReset

自定义Loader销毁后

各方法执行顺序：

onCreateLoader
onStartLoading
loadInBackground

示例代码

实现LoaderCallbacks接口所在类：

import android.app.LoaderManager;
import android.content.Loader;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import io.githubs.grooters.luffy.R;
public class LoaderActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Integer>{
    private static final String TAG= LoaderActivity.class.getSimpleName();
    private AsyncTasker asyncTasker;
    @Override
    protected void onCreate(@Nullable final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_loader);
        getLoaderManager().initLoader(1,savedInstanceState,this);

    @Override
    public void onLoadFinished(Loader loader, Integer i) {
        Log.i(TAG,"onLoadFinished："+i);
    }

    @Override
    public Loader onCreateLoader(int i, Bundle bundle) {
        Log.i(TAG,"onCreateLoader");
        CustomLoader customLoader=new CustomLoader(this);
        customLoader.getInfo("LoaderActivity");
        return customLoader;
    }

    @Override
    public void onLoaderReset(Loader loader) {
        Log.i(TAG,"onLoaderReset");
    }
}

自定义Loader：

import android.content.AsyncTaskLoader;
import android.content.Context;
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import luffy_intent.Intenter;

public class CustomLoader extends AsyncTaskLoader<Integer> {

    private static final String TAG=CustomLoader.class.getSimpleName();
    public CustomLoader(@NonNull Context context) {
        super(context);
        Log.i(TAG,"CustomLoader");
    }
    @Override
    protected void onStartLoading() {
        super.onStartLoading();
        Log.i(TAG,"onStartLoading");
        forceLoad();
    }
    @Nullable
    @Override
    public Integer loadInBackground() {
        Log.i(TAG,"loadInBackground");
        int i=0;
        while(i<10){
            try {
                Thread.sleep(1000);
                ++i;
                Log.i(TAG,"i: "+i);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            Log.i(TAG,"Finish");
        }
        return i;
    }
    @Override
    protected boolean onCancelLoad() {
        Log.i(TAG,"onCancelLoad");
        return super.onCancelLoad();
    }
    public void getInfo(String str){
        Log.i(TAG,"getInfo："+str);
    }
}