AS Workshop - part 2

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
    <ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/qr_code"
    android:scaleType="fitCenter"
    android:background="@android:color/transparent" />
    
    
<com.baoyz.widget.PullRefreshLayout
    android:id="@+id/swipeRefreshLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"></ListView>

</com.baoyz.widget.PullRefreshLayout>

</RelativeLayout>

build.gradle

apply plugin: 'com.android.application'

repositories {
    flatDir {
        dirs 'libs'
    }
}


android {
    compileSdkVersion 21
    buildToolsVersion "21.1.1"

    defaultConfig {
        applicationId "tw.com.akdg.helloandroidstudio"
        minSdkVersion 15
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'

    //QR
    compile 'com.google.zxing:javase:2.0'

    compile(name:'library-release', ext:'aar')
}

MainActivity

package tw.com.akdg.helloandroidstudio;

import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.widget.ImageView;

import com.baoyz.widget.PullRefreshLayout;
import com.google.zxing.EncodeHintType;

import java.util.HashMap;


public class MainActivity extends Activity {

    public static final String TAG = "MainActivity";
    private DisplayMetrics metrics;
    private ImageView QR_code;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final PullRefreshLayout layout = (PullRefreshLayout) findViewById(R.id.swipeRefreshLayout);

// listen refresh event
        layout.setOnRefreshListener(new PullRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                layout.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        metrics = getResources().getDisplayMetrics();
                        QR_code = (ImageView) findViewById(R.id.qr_code);
                        try {
                            createQRcode("http://goo.gl/2SJIkk");
                        } catch (Exception e) {
                            Log.e(TAG, "createQRcode failed", e);
                        }
                        layout.setRefreshing(false);
                    }
                }, 4000);
            }
        });

        layout.setRefreshing(true);
        layout.setRefreshStyle(PullRefreshLayout.STYLE_CIRCLES);



    }

    private void createQRcode(final String content) throws Exception {
        try {
            final Bitmap bitmap = encodeAsBitmap(content, com.google.zxing.BarcodeFormat.QR_CODE, metrics.widthPixels, metrics.widthPixels);
            if (null != bitmap) {
                QR_code.setImageBitmap(bitmap);
            }
        } catch (Exception e) {
            throw e;
        } finally {

        }
    }

    private Bitmap encodeAsBitmap(String contents, com.google.zxing.BarcodeFormat format,
                                  int desiredWidth, int desiredHeight) throws com.google.zxing.WriterException {
        final int WHITE = this.getResources().getColor(android.R.color.transparent);
        final int BLACK = 0xFF000000;

        HashMap<EncodeHintType, String> hints = null;
        String encoding = guessAppropriateEncoding(contents);
        if (encoding != null) {
            hints = new HashMap<EncodeHintType, String>(2);
            hints.put(com.google.zxing.EncodeHintType.CHARACTER_SET, encoding);
        }
        com.google.zxing.MultiFormatWriter writer = new com.google.zxing.MultiFormatWriter();
        com.google.zxing.common.BitMatrix result = writer.encode(contents, format, desiredWidth,
                desiredHeight, hints);
        int width = result.getWidth();
        int height = result.getHeight();
        int[] pixels = new int[width * height];
        // All are 0, or black, by default
        for (int y = 0; y < height; y++) {
            int offset = y * width;
            for (int x = 0; x < width; x++) {
                pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
            }
        }

        Bitmap bitmap = Bitmap.createBitmap(width, height,
                Bitmap.Config.ARGB_8888);
        bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
        return bitmap;
    }

    private static String guessAppropriateEncoding(CharSequence contents) {
        // Very crude at the moment
        for (int i = 0; i < contents.length(); i++) {
            if (contents.charAt(i) > 0xFF) {
                return "UTF-8";
            }
        }
        return null;
    }

}