简单实现断点续传

先导XUtil架包:xUtils-2.6.14.jar

加入依赖: compile ‘org.xutils:xutils:3.2.2’

Main页面

import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ProgressBar;import android.widget.TextView;import android.widget.Toast;import com.lidroid.xutils.HttpUtils;import com.lidroid.xutils.exception.HttpException;import com.lidroid.xutils.http.ResponseInfo;import com.lidroid.xutils.http.callback.RequestCallBack;import java.io.File;public class MainActivity extends AppCompatActivity implements View.OnClickListener{    private ProgressBar pb;    private TextView tv_error;    private TextView tv_progress;    private Button btn_down;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 初始化        pb = (ProgressBar) findViewById(R.id.pb);        tv_progress = (TextView) findViewById(R.id.tv_progress);        tv_error = (TextView) findViewById(R.id.tv_failure);        btn_down = (Button) findViewById(R.id.btn_down);        // 开始点击事件        btn_down.setOnClickListener(this);    }    @Override    public void onClick(View view) {        String fileName = "weixin_821.apk";        String path = "http://gdown.baidu.com/data/wisegame/df65a597122796a4/" + fileName;        HttpUtils http = new HttpUtils();        http.download(path, Environment.getExternalStorageDirectory() + "/"                + fileName, true, true, new RequestCallBack<File>() {            @Override            public void onSuccess(ResponseInfo<File> arg0) {                // 下载成功                Toast.makeText(MainActivity.this, arg0.result.getPath(), Toast.LENGTH_SHORT).show();            }//            @Override//            public void onFailure(com.lidroid.xutils.exception.HttpException e, String s) {//                tv_error.setText(s);//            }            @Override            public void onFailure(HttpException arg0, String arg1) {                // 下载失败                tv_error.setText(arg1);            }            @Override            public void onLoading(long total, long current, boolean isUploading) {                super.onLoading(total, current, isUploading);                // 下载任务                pb.setMax((int) total);                pb.setProgress((int) current);                tv_progress.setText(current * 100 / total + "%");            }        });    }}

main布局

 <Button        android:id="@+id/btn_down"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="开始下载" />    <TextView        android:id="@+id/tv_failure"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <ProgressBar        android:id="@+id/pb"        style="@android:style/Widget.ProgressBar.Horizontal"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <TextView        android:id="@+id/tv_progress"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="下载进度" />

权限

               <action android:name="android.intent.action.MAIN" />               <category android:name="android.intent.category.LAUNCHER"/>