I made a simple app of android webview a few days ago and it runs fine but the problem is happening now that after some time the app is not open, that screen is going black and reinstall After doing it, it is going right, for some time it is going right, then the same problem is coming, if someone helps, it will be very kind.
Mi redmi note 6 Pro Android V 9 PIE
Source Code
manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.musicwala.djaman" >
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <application
        android:allowBackup="true"
        android:usesCleartextTraffic="true"
        android:icon="@drawable/main"
        android:label="@string/app_name"
        android:theme="@style/AppTheme"
        android:resizeableActivity="true">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" 
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".web_main">
        </activity>
        <activity
            android:name=".setting">
        </activity>
        <activity
            android:name=".about"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
        </activity>
        <activity
            android:name=".update">
        </activity>
        <activity
            android:name=".download">
        </activity>
        <activity android:name=".play_ui"
            android:theme="@style/Theme.AppCompat.Light">
        </activity>
    </application>
</manifest>
build.gradle
apply plugin: 'com.android.application'
android {
    compileSdkVersion 29
    defaultConfig {
        applicationId "com.musicwala.djaman"
        minSdkVersion 14
        targetSdkVersion 29
        versionCode 3
        versionName "3.1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    compile ('android.arch.core:runtime:+') {
       force = true
}   
    compile 'com.android.support:appcompat-v7:27.+'
    compile fileTree(dir: 'libs', include: ['*.jar'])
}
MainActivity.java
package com.musicwala.djaman;
import android.app.*;
import android.os.*;
import android.view.Window;
import android.widget.AbsoluteLayout.LayoutParams;
import android.view.WindowManager;
import android.content.Intent;
import android.util.Log;
import android.net.NetworkInfo;
import android.net.ConnectivityManager;
import android.content.Context;
import android.content.DialogInterface;
import android.provider.Settings;
import android.widget.Toast;
public class MainActivity extends Activity 
{
    
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        //requestWindowFeature(Window.FEATURE_NO_TITLE);
      //  getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                            // WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.main);
        
        if(isNetworkConnectionAvailable() == true)
        {
            final Handler h = new Handler();
            h.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        //Do something after 1s   
                        Intent intent = new Intent(MainActivity.this,web_main.class);
                        startActivity(intent);
                        finish();
                    }
                }, 1000);
            
        }
    
    }
    public void checkNetworkConnection(){
        AlertDialog.Builder builder =new AlertDialog.Builder(MainActivity.this);
        builder.setTitle("No internet Connection");
        builder.setMessage("Please turn on internet connection to continue!");
        builder.setPositiveButton("Turn On", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    MainActivity.this.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
                }
            }).show();
        builder.setNegativeButton("Exit", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    finishAffinity();
                }
            }).show();
        AlertDialog alertDialog = builder.create();
        alertDialog.show();
        
    }
    public boolean isNetworkConnectionAvailable(){
        ConnectivityManager cm =
            (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null &&
            activeNetwork.isConnected();
        if(isConnected) {
            Log.d("Network", "Connected");
            return true;
        }
        else{
            checkNetworkConnection();
            Log.d("Network","Not Connected");
            return false;
        }
    }
    
    
}
And is working fine in my other device
Android v8.0 Oreo