Android应用安装、卸载、状态、打开及Android7以上文件权限设置

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.provider.Settings;

import androidx.annotation.RequiresApi;
import androidx.core.content.FileProvider;

import java.io.File;

public class AppInstallUtils {
    private Activity mAct;
    private String mPath;//下载下来后文件的路径
    public static int UNKNOWN_CODE = 2018;

    public AppInstallUtils(Activity mAct, String mPath) {
        this.mAct = mAct;
        this.mPath = mPath;
    }

    public void install() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) startInstallO();
        else startInstallN();
    }

    /**
     * android1.x-6.x
     */
    private void startInstall() {
        Intent install = new Intent(Intent.ACTION_VIEW);
        install.setDataAndType(Uri.parse("file://" + mPath), "application/vnd.android.package-archive");
        install.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        mAct.startActivity(install);
    }

    /**
     * android7.x
     */
    private void startInstallN() {
        //参数1 上下文, 参数2 在AndroidManifest中的android:authorities值, 参数3  共享的文件
        Uri apkUri = FileProvider.getUriForFile(mAct, mAct.getApplicationContext().getPackageName() + ".fileprovider", new File(mPath));
        Intent install = new Intent(Intent.ACTION_VIEW);
        //由于没有在Activity环境下启动Activity,设置下面的标签
        install.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        //添加这一句表示对目标应用临时授权该Uri所代表的文件
        install.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        install.setDataAndType(apkUri, "application/vnd.android.package-archive");
        mAct.startActivity(install);
    }

    /**
     * android8.x
     */
    @RequiresApi(api = Build.VERSION_CODES.O)
    private void startInstallO() {
        boolean isGranted = mAct.getPackageManager().canRequestPackageInstalls();
        if (isGranted) startInstallN();//安装应用的逻辑(写自己的就可以)
        else new AlertDialog.Builder(mAct)
                .setCancelable(false)
                .setTitle("安装应用需要打开未知来源权限，请去设置中开启权限")
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface d, int w) {
                        Intent intent = new Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);
                        mAct.startActivityForResult(intent, UNKNOWN_CODE);
                    }
                })
                .show();
    }
}

public static void openApp(Activity activity,String packageName){
    Intent launchIntent = activity.getPackageManager().getLaunchIntentForPackage(packageName);
    if (launchIntent != null) {
        activity.startActivity(launchIntent);
    } else {
        // 应用未安装或包名无效
        Toast.makeText(activity, "应用未安装或包名无效", Toast.LENGTH_SHORT).show();
    }
}

<manifest>
    <application>
        <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="cn.psvmc.myapp.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
             <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_path" />
        </provider>
    </application>
</manifest>

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="cn.psvmc.myapp.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_path" />
</provider>

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path
        name="files"
        path="images/" />
    <cache-path
        name="cache"
        path="." />
    <external-path
        name="external"
        path="." />
    <external-files-path
        name="external-files"
        path="." />
    <external-cache-path
        name="external-cache"
        path="." />
    <external-media-path
        name="external-media"
        path="." />
</paths>

<files-path name="files" path="images/" />

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <!--定义APP的存放目录-->
    <external-path
        name="AppInstaller"
        path="/Download"></external-path>
</paths>

//文件路径
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getCanonicalPath() + "/apps/MyApp.apk");
//获取文件对应的content类型Uri
Uri uri = FileProvider.getUriForFile(this, "cn.psvmc.myapp.fileprovider", file);

//普通的fileUri（通过Uri.fromFile(file)获取）
file:///storage/emulated/0/Download/apps/MyApp.apk
//contentUri
content://cn.psvmc.myapp.fileprovider/AppInstaller/apps/MyApp.apk

//文件路径
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getCanonicalPath() + "/MyApp.apk");
Intent intent = new Intent(Intent.ACTION_VIEW);
//获取文件对应的content类型Uri
Uri uri = FileProvider.getUriForFile(this, "cn.psvmc.myapp.fileprovider", file);
intent.setDataAndType(uri, "application/vnd.android.package-archive");
//intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//可以不加
intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
startActivity(intent);