1.配置：
1.1 AndroidManifest.xml中添加权限和FileProvider：
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"android.permission.INTERNET"/>
"android.permission.READ_EXTERNAL_STORAGE"/>
"android.permission.WRITE_EXTERNAL_STORAGE"/>
"android.permission.REQUEST_INSTALL_PACKAGES" />
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"androidx.core.content.FileProvider"
android:authorities="com.fengzhi.wuyemanagement.fileprovider"
android:grantUriPermissions="true"
android:exported="false">
"android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
复制代码 1.2 新建文件（路径：res\xml\file_paths.xml）:
"." name="external_storage_root" />
复制代码1.3 (app的)build.gradle:
implementation "com.lzy.net:okgo:3.0.4"//okgo 网络请求
implementation 'com.google.code.gson:gson:2.8.2'//gson
implementation "org.permissionsdispatcher:permissionsdispatcher:4.3.1"//权限
annotationProcessor "org.permissionsdispatcher:permissionsdispatcher-processor:4.3.1"//权限
复制代码2.这里以点击按钮进行更新为例：
2.1 核心代码：
private int version;
/* 更新进度条 */
private ProgressBar mProgress;
private AlertDialog mDownloadDialog;
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//点击按钮，检查权限，，，检查更新的方法
@NeedsPermission({Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.REQUEST_INSTALL_PACKAGES})
protected void checkUpdate() {
showLoadingDialog("检测更新中...");
version = AppUpdateUtil.getAppVersionCode(this);//检查当前版本号
// 调用方法，，，接口的具体实现，接收传过来的参数，再调自己的方法，
requestAppUpdate(version, new DataRequestListener() {
@Override
public void success(UpdateAppBean data) {
// 返回的json，getStatus为0时，去下载apk文件,这里是下载apk文件的方法
updateApp(data.getData().getApk_url());
}
@Override
public void fail(String msg) {
// 返回的json，getStatus为1时，提示："已是最新版本！"
SToast(msg);
dismissLoadingDialog();
}
});
}
//检查版本号，第一次请求(post)，，，UpdateAppBean根据服务器返回生成
private void requestAppUpdate(int version, final DataRequestListener listener) {
OkGo.post(Const.HOST_URL + Const.UPDATEAPP).params("version", version).execute(new StringCallback() {
@Override
public void onSuccess(Response response) {
Gson gson = new Gson();
UpdateAppBean updateAppBean = gson.fromJson(response.body(), UpdateAppBean.class);
if (updateAppBean.getStatus() == 0) {
listener.success(updateAppBean);
} else {
listener.fail(updateAppBean.getMsg());
}
}
@Override
public void onError(Response response) {
listener.fail("服务器连接失败");
dismissLoadingDialog();
}
});
}
//如果有新版本，提示有新的版本，然后下载apk文件
private void updateApp(String apk_url) {
dismissLoadingDialog();
DialogUtils.getInstance().showDialog(this, "发现新的版本，是否下载更新？",
new DialogUtils.DialogListener() {
@Override
public void positiveButton() {
downloadApp(apk_url);
}
});
}
//下载apk文件并跳转(第二次请求，get)
private void downloadApp(String apk_url) {
OkGo.get(apk_url).tag(this).execute(new FileCallback() {
@Override
public void onSuccess(Response response) {
String filePath = response.body().getAbsolutePath();
Intent intent = IntentUtil.getInstallAppIntent(mContext, filePath);
// 测试过这里必须用startactivity，不能用stratactivityforresult
mContext.startActivity(intent);
dismissLoadingDialog();
mDownloadDialog.dismiss();
mDownloadDialog=null;
}
@Override
public void downloadProgress(Progress progress) {
// showDownloadDialog();
// mProgress.setProgress((int) (progress.fraction * 100));
if (mDownloadDialog == null) {
// 构造软件下载对话框
AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
builder.setTitle("正在更新");
// 给下载对话框增加进度条
final LayoutInflater inflater = LayoutInflater.from(mContext);
View v = inflater.inflate(R.layout.item_progress, null);
mProgress = (ProgressBar) v.findViewById(R.id.update_progress);
builder.setView(v);
mDownloadDialog = builder.create();
mDownloadDialog.setCancelable(false);
mDownloadDialog.show();
}
mProgress.setProgress((int) (progress.fraction * 100));
}
});
}
复制代码 2.2 DataRequestListener：
public interface DataRequestListener {
//请求成功
void success(T data);
//请求失败
void fail(String msg);
}
复制代码 接下来是工具类，来自github，参考，github.com/vondear/RxT…
2.3 AppUpdateUtil：
/**
* 获取App版本码
*
* @param context 上下文
* @return App版本码
*/
public static int getAppVersionCode(Context context) {
return getAppVersionCode(context, context.getPackageName());
}
复制代码2.4 IntentUtil：
public class IntentUtil {
/**
* 获取安装App(支持7.0)的意图
*
* @param context
* @param filePath
* @return
*/
public static Intent getInstallAppIntent(Context context, String filePath) {
//apk文件的本地路径
File apkfile = new File(filePath);
if (!apkfile.exists()) {
return null;
}
Intent intent = new Intent(Intent.ACTION_VIEW);
Uri contentUri = FileUtil.getUriForFile(context, apkfile);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
}
intent.setDataAndType(contentUri, "application/vnd.android.package-archive");
return intent;
}
复制代码2.5 FileUtil：
/**
* 将文件转换成uri(支持7.0)
*
* @param mContext
* @param file
* @return
*/
public static Uri getUriForFile(Context mContext, File file) {
Uri fileUri = null;
if (Build.VERSION.SDK_INT >= 24) {
fileUri = FileProvider.getUriForFile(mContext, mContext.getPackageName() + ".fileprovider", file);
} else {
fileUri = Uri.fromFile(file);
}
return fileUri;
}
复制代码3.遇到的问题
9.0手机authorities配置出错，导致无法安装， 解决办法：
1.项目中使用了Androidx，AndroidManifest.xml的配置中就必须使用androidx的fileprovider2.这里的authorities与FileUtil.java中的要一样，我就是字母P大写了导致错误