ERROR - The number of method references in a .dex file cannot exceed 64K.

In build.gradle ,

defaultConfig{

 multiDexEnabled true

 dependency
 configurations
{
        compile.exclude group: "org.apache.httpcomponents", module: "httpclient"
}

}

How to resolve org.apache.http does not exist

Error:(6, 23) error: package org.apache.http does not exist
Solution:

If you are using target sdk as 23 add below code in your build.gradle

android{
    compileSdkVersion 23
    buildToolsVersion '23.0.1'
    useLibrary  'org.apache.http.legacy'
}

Prevent webview from showing "web page not available"

Apply the below Code,

WebView.setWebViewClient(new WebViewClient() {
    public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
        WebView.loadUrl("file:///android_asset/myerrorpage.html");

    }
});

Android Internet Connection checking

private boolean isNetworkConnected() 

{

ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo ni = cm.getActiveNetworkInfo();
if (ni == null) 

{
       //There are no active networks.       return false;
} 

else
{

        return true;
}

}

The above function will return true only if the device has internet connection otherwise false.

manifest file permissions,

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

WebView Unicode Support

mWebView.loadDataWithBaseURL(null, "தமிழில் கணினி", "text/html", "utf-8", null);
OR
WebSettings settings = mWebView.getSettings();
settings.setDefaultTextEncodingName("utf-8");

Load Image from URL

Use the following code to display the picture in ImageView,
URL url = new URL("http://www.vijaynetwork.com/vijay_top_logo.jpg");
Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bmp);

How to open a new layout after button click in android

Use the below code,

 Button next = (Button) findViewById(R.id.mybutton1);

next.setOnClickListener(new View.OnClickListener()
{
            public void onClick(View view)
          {
                Intent myIntent = new Intent(view.getContext(), my_activity.class);
                startActivityForResult(myIntent, 0);
            }

   });