Unable to access mysql database from my android application

Question

I'm trying to insert values into mysql database using below code. For some reason the app crashes everytime I press the submit button. I added Internet permission too. I am unable to understand the logcat. Any help will be appreciated.

MainActivity.java

package com.example.testthis;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity {

    EditText et;
    Button btn;
    String mname;
    String query;
    String mylink;
    Activity context;
    ProgressDialog pd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et = (EditText)findViewById(R.id.editText1);
        btn = (Button)findViewById(R.id.button1);
        btn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                mname = et.getText().toString();

                try {

                    query = URLEncoder.encode(mname,"utf-8");

                } catch (UnsupportedEncodingException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                mylink = "http://necrecords.16mb.com/donordetails.php?fn="+query;

                HttpAsyncTask hat = new HttpAsyncTask();

                hat.execute(mylink);

            }



        });


    }

    private class HttpAsyncTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... urls) {

            return httpRequestResponse(urls[0]);
        }

        protected void onPreExecute(){
            super.onPreExecute();
            pd = new ProgressDialog(context);
            pd.setTitle("Reporting query");
            pd.setMessage("Please wait..");
            pd.setCancelable(true);
            pd.setIndeterminate(true);
            pd.show();

        }
        // onPostExecute displays the results of the AsyncTask.
        @Override
        protected void onPostExecute(String result) {

            if(pd!=null) pd.dismiss();
            Toast.makeText(getApplicationContext(),"Successfully Sent!", Toast.LENGTH_LONG).show();

        }
    }

//For HttpAsync Functions: sending requests and receiving responses
    public static String httpRequestResponse(String url){
        InputStream inputStream = null;
        String result = "";
        try {
            // create HttpClient
            HttpClient httpclient = new DefaultHttpClient();

            // make GET request to the given URL
            HttpResponse httpResponse = httpclient.execute(new HttpGet(url));

            // receive response as inputStream
            inputStream = httpResponse.getEntity().getContent();

            // convert InputStream to string
            if(inputStream != null)
                result = convertInputStreamToString(inputStream);
            else
                result = "InputStream did not work";


        } catch (Exception e) {
            Log.d("InputStream", e.getLocalizedMessage());
        }

        return result;
    }

private static String convertInputStreamToString(InputStream inputStream) throws IOException{
    BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
    String line = "";
    String result = "";
    while((line = bufferedReader.readLine()) != null)
        result += line;

    inputStream.close();
    return result;
}


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Logcat

04-21 19:34:24.582: I/dalvikvm(5064): Could not find method android.view.ViewGroup.onNestedScrollAccepted, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onNestedScrollAccepted
    04-21 19:34:24.582: W/dalvikvm(5064): VFY: unable to resolve virtual method 12215: Landroid/view/ViewGroup;.onNestedScrollAccepted (Landroid/view/View;Landroid/view/View;I)V
    04-21 19:34:24.582: D/dalvikvm(5064): VFY: replacing opcode 0x6f at 0x0000
    04-21 19:34:24.582: I/dalvikvm(5064): Could not find method android.view.ViewGroup.onStopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onStopNestedScroll
    04-21 19:34:24.582: W/dalvikvm(5064): VFY: unable to resolve virtual method 12221: Landroid/view/ViewGroup;.onStopNestedScroll (Landroid/view/View;)V
    04-21 19:34:24.582: D/dalvikvm(5064): VFY: replacing opcode 0x6f at 0x0000
    04-21 19:34:24.582: I/dalvikvm(5064): Could not find method android.support.v7.internal.widget.ActionBarOverlayLayout.stopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.setHideOnContentScrollEnabled
    04-21 19:34:24.582: W/dalvikvm(5064): VFY: unable to resolve virtual method 9785: Landroid/support/v7/internal/widget/ActionBarOverlayLayout;.stopNestedScroll ()V
    04-21 19:34:24.582: D/dalvikvm(5064): VFY: replacing opcode 0x6e at 0x000e
    04-21 19:34:24.592: I/dalvikvm(5064): Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
    04-21 19:34:24.592: W/dalvikvm(5064): VFY: unable to resolve virtual method 399: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
    04-21 19:34:24.592: D/dalvikvm(5064): VFY: replacing opcode 0x6e at 0x0002
    04-21 19:34:24.592: I/dalvikvm(5064): Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
    04-21 19:34:24.592: W/dalvikvm(5064): VFY: unable to resolve virtual method 421: Landroid/content/res/TypedArray;.getType (I)I
    04-21 19:34:24.592: D/dalvikvm(5064): VFY: replacing opcode 0x6e at 0x0002
    04-21 19:34:24.592: I/dalvikvm(5064): Could not find method android.content.res.Resources.getDrawable, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawable
    04-21 19:34:24.592: W/dalvikvm(5064): VFY: unable to resolve virtual method 362: Landroid/content/res/Resources;.getDrawable (ILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
    04-21 19:34:24.592: D/dalvikvm(5064): VFY: replacing opcode 0x6e at 0x0002
    04-21 19:34:24.592: I/dalvikvm(5064): Could not find method android.content.res.Resources.getDrawableForDensity, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawableForDensity
    04-21 19:34:24.592: W/dalvikvm(5064): VFY: unable to resolve virtual method 364: Landroid/content/res/Resources;.getDrawableForDensity (IILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
    04-21 19:34:24.592: D/dalvikvm(5064): VFY: replacing opcode 0x6e at 0x0002
    04-21 19:34:24.622: D/TextView(5064): Constructor - Got Res id for appearance for textColorPrimaryInverse
    04-21 19:34:24.622: W/ResourceType(5064): Skipping entry 0x7f070035 in package table 0 because it is not complex!
    04-21 19:34:24.622: D/TextView(5064): Constructor - Got appearance for textColorPrimaryInverse
    04-21 19:34:24.622: D/TextView(5064): Constructor -- Got mEditTextBackgroundColor
    04-21 19:34:24.702: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 46
    04-21 19:34:24.712: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 49
    04-21 19:34:24.712: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 50
    04-21 19:34:24.712: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 50
    04-21 19:34:24.712: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 50
    04-21 19:34:24.722: E/IMGSRV(5064): :0: PVRDRMOpen: TP3, ret = 52
    04-21 19:34:24.762: D/OpenGLRenderer(5064): Enabling debug mode 0
    04-21 19:34:30.742: D/AndroidRuntime(5064): Shutting down VM
    04-21 19:34:30.742: W/dalvikvm(5064): threadid=1: thread exiting with uncaught exception (group=0x430ef140)
    04-21 19:34:30.742: E/AndroidRuntime(5064): FATAL EXCEPTION: main
    04-21 19:34:30.742: E/AndroidRuntime(5064): Process: com.example.testthis, PID: 5064
    04-21 19:34:30.742: E/AndroidRuntime(5064): java.lang.NullPointerException
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.AlertDialog.<init>(AlertDialog.java:98)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.ProgressDialog.<init>(ProgressDialog.java:77)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.example.testthis.MainActivity$HttpAsyncTask.onPreExecute(MainActivity.java:88)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.AsyncTask.execute(AsyncTask.java:535)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.example.testthis.MainActivity$1.onClick(MainActivity.java:67)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.view.View.performClick(View.java:4478)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.view.View$PerformClick.run(View.java:18698)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Handler.handleCallback(Handler.java:733)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Handler.dispatchMessage(Handler.java:95)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Looper.loop(Looper.java:149)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.ActivityThread.main(ActivityThread.java:5257)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at java.lang.reflect.Method.invokeNative(Native Method)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at java.lang.reflect.Method.invoke(Method.java:515)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
    04-21 19:34:30.742: E/AndroidRuntime(5064):     at dalvik.system.NativeStart.main(Native Method)

Ivan Nikolov · Accepted Answer · 2015-04-21 14:44:44Z

1

Line 37:

Activity context;

Then you never initialize this variable and on line 88 you get a null pointer exception:

pd = new ProgressDialog(context);

That's what the log tells you: NullPointerException.

EDIT: Just to clarify for Popsta. Here is the fragment from the logcat that helped me figure out what's going on (just at the very end):

04-21 19:34:30.742: E/AndroidRuntime(5064): java.lang.NullPointerException
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.AlertDialog.<init>(AlertDialog.java:98)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.ProgressDialog.<init>(ProgressDialog.java:77)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.example.testthis.MainActivity$HttpAsyncTask.onPreExecute(MainActivity.java:88)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.AsyncTask.execute(AsyncTask.java:535)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.example.testthis.MainActivity$1.onClick(MainActivity.java:67)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.view.View.performClick(View.java:4478)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.view.View$PerformClick.run(View.java:18698)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Handler.handleCallback(Handler.java:733)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Handler.dispatchMessage(Handler.java:95)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.os.Looper.loop(Looper.java:149)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at android.app.ActivityThread.main(ActivityThread.java:5257)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at java.lang.reflect.Method.invokeNative(Native Method)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at java.lang.reflect.Method.invoke(Method.java:515)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
04-21 19:34:30.742: E/AndroidRuntime(5064):     at dalvik.system.NativeStart.main(Native Method)

edited Apr 21, 2015 at 14:44

answered Apr 21, 2015 at 14:29

Ivan Nikolov

7834 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Popsta Over a year ago

Sir you answer solved my problem. Does the logcat particularly shows that the NullpointerException is due to context?

Ivan Nikolov Over a year ago

Yes, it does. Ignore the text in the beginning - it's just a timestamp and some extra info. Read the things after that. Whenever you have issues, just look there for exceptions and you will figure it out. I edited my answer to be clearer for you.

Ivan Nikolov Over a year ago

It doesn't clearly say it's due to the context. It says which line and file it occurred on (at com.example.testthis.MainActivity$HttpAsyncTask.onPreExecute(MainActivity.java:88)). I just looked at what you're doing on the line.

Chris Stratton Over a year ago

The existence of that variable is highly suspect anyway. An inner class could typically use MainActivity.this where it needs a reference to the instance of the containing Activity.

Collectives™ on Stack Overflow

Unable to access mysql database from my android application

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related