Android webview loading data performance very slow

Question

Hi I am working on one application, In that I am using Android WebView. Whenever I launch webview activity, loading data in string html format from test.txt file. test.txt file contains nearly 2.5 MB data, after loading test.txt file, if slide screen to end to read all data and press back. Then subsequent launch of webview activity taking more time to render data. In first launch of webview its taking minimal time. I am not getting any error/exception/crash in between launching this activity.

I am using Android API level 18 and above

Note: I did lot of research on this issue. I tried Solution from Android webview slow and Android WebView performance no use.

I can't make android:hardwareAccelerated="true" <-- why because it has lot of side effects (Still I used this one, but no changes I found on this issue).

I can't use webview.getSettings().setRenderPriority(RenderPriority.HIGH);

setRenderPriority() --> This method was deprecated in API level 18. It is not recommended to adjust thread priorities, and this will not be supported in future versions.

My DataLoader.java class

public class DataLoader extends Activity {

    private WebView webView = null;
    // Progress Dialog
    private ProgressDialog progressDialog;

    String dataContent = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.web_view);
        webView = (WebView)findViewById(R.id.text);

        // Loading webview in Background Thread
        new LoadWebView().execute();
    }

    class LoadWebView extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressDialog = new ProgressDialog(DataLoader.this);
            progressDialog.setTitle("Loading...");
            progressDialog.setMessage("Please wait.");
            progressDialog.setCancelable(false);
            progressDialog.setIndeterminate(true);
            progressDialog.show();
        }

        protected String doInBackground(String... args) {
            // AssetFileReader read the txt file and return data in the form of string
            dataContent = AssetFileReader.read(getApplicationContext(), "test.txt");

            return null;
        }

        protected void onPostExecute(String str) {
            // dismiss the dialog
            progressDialog.dismiss();

            if (dataContent != null) {
                // updating UI from Background Thread
                runOnUiThread(new Runnable() {
                    public void run() {

                        WebSettings s = webView.getSettings();
                        s.setUseWideViewPort(true);
                        s.setSupportZoom(true);
                        s.setBuiltInZoomControls(true);
                        s.setDisplayZoomControls(false);
                        s.setJavaScriptEnabled(true);
                        webView.loadData(dataContent, "text/html", "utf-8");
                    }
                });
            }
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        webView.clearCache(true);
        webView.clearHistory();
    }
}

my web_view.xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <WebView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/text">
    </WebView>

</LinearLayout>

please let me know if you have any work around on this issue.

Answer 1

I think the following works best:

if (Build.VERSION.SDK_INT >= 19) {
    webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
}       
else {
    webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}

Android 19 has Chromium engine for WebView. I guess it works better with hardware acceleration.

For more info Android 4.4 KitKat, the browser and the Chrome WebView

Hardware Acceleration also do's the trick.You can use it in different levels in your application.

Application level

<application android:hardwareAccelerated="true" ...>

Activity level

<application android:hardwareAccelerated="true">
    <activity ... />
    <activity android:hardwareAccelerated="false" />
</application>

Window level

getWindow().setFlags(
    WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
    WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

View level

myView.setLayerType(View.LAYER_TYPE_HARDWARE, null);

But as already mentioned in your question can you elaborate the side effects for this ?