Android 8.0安装apk的正确姿势

在8.0的系统版本中，安装apk时有一层膜，现在就要捅了它，不然就是一闪而过，安装不上。这层膜就是​​允许安装未知应用​​

在8.0中这个选项默认是false，只需要打开一次即可

1、manifest中添加权限

<!-- 8.0安装未知应用来源 -->
    <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>

2、判断是不是8.0

if (Build.VERSION.SDK_INT >= 26) {
    boolean b = context.getPackageManager().canRequestPackageInstalls();
    if (b) {
        installApk();//安装应用
    } else {
    //请求安装未知应用来源的权限
    ActivityCompat.requestPermissions(ActivityUtil.getCurrentActivity(), new String[]{Manifest.permission.REQUEST_INSTALL_PACKAGES}, INSTALL_PACKAGES_REQUESTCODE);
    dialog.dismiss();
} else {
    installApk();
    dialog.dismiss();
}

处理回调

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case INSTALL_PACKAGES_REQUESTCODE:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    installApk();
                } else {
                    Intent intent = new Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);
                    startActivityForResult(intent, GET_UNKNOWN_APP_SOURCES);
                }
                break;

        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case GET_UNKNOWN_APP_SOURCES:
                installApk();
                break;
        }
    }