一.在 AndroidManifest 需要给权限:
//联网权限
<uses-permission android:name="android.permission.INTERNET"/>
//写权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
//读权限
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
二.Java 文件全部内容(使用字节流读写数据):
//将本地资源下载到内置存储卡(私有目录)
public class DownLoadText extends Activity implements View.OnClickListener{
Button btn_downloadmovie;
ProgressBar progressbar;
private static final String sourceFile = "111.png" ; //可通过修改名字读取不同文件
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
initListener();
handlePermission();
}
/**
* 动态请求写权限
* 检查 app 是否拥有存储权限,如果没有的话,提醒用户开启权限
*/
public void handlePermission() {
// 检查是否开启 Manifest.permission.xxx
// (xxx 为权限,根据自己需求添加)
if (ActivityCompat.checkSelfPermission(this,
Manifest.permission.WRITE_EXTERNAL_STORAGE) ==
PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "Permission has been allowed",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "ask for permission",Toast.LENGTH_SHORT).show();
// 请求权限
ActivityCompat.requestPermissions(this, new String[]
{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
Log.d(TAG, "handlePermission: has aksed");