26 Mar 2014

Snippet: align a TextView around an image

In this post I will describe how to realize a particular layout not very common on Android: a text around an image.

This layout is not an Android Pattern, but it can be useful in same cases.
As always it is just an example, and you should improve some points in your real project.

Use a simple layout:

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

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:id="@+id/text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:text="Medium Text"
            android:textAppearance="?android:attr/textAppearanceMedium" />

        <ImageView
            android:id="@+id/icon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/airport1" />
    </RelativeLayout>


</ScrollView>

To achieve our scope, we can use a LeadingMarginSpan.LeadingMarginSpan2.
This span allows the implementor to specify the number of lines of text to which this object is attached that the "first line of paragraph" margin width will be applied to.

 /**
     *
     */
    class MyLeadingMarginSpan2 implements LeadingMarginSpan.LeadingMarginSpan2 {

        private int margin;
        private int lines;

        MyLeadingMarginSpan2(int lines, int margin) {
            this.margin = margin;
            this.lines = lines;
        }

        /**
         * Apply the margin
         *
         * @param first
         * @return
         */
        @Override
        public int getLeadingMargin(boolean first) {
            if (first) {
                return margin;
            } else {
                return 0;
            }
        }

        @Override
        public void drawLeadingMargin(Canvas c, Paint p, int x, int dir,
                                      int top, int baseline, int bottom, CharSequence text,
                                      int start, int end, boolean first, Layout layout) {}


        @Override
        public int getLeadingMarginLineCount() {
            return lines;
        }
    };

We only need to calculate the number of lines where we would like applying a margin and the right margin.
In this case we will get number of lines = height of image and margin = width of image + little extra margin. 

public class MainActivity extends Activity {

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

        mTextView = (TextView) findViewById(R.id.text);
        mImageView = (ImageView) findViewById(R.id.icon);


        final ViewTreeObserver vto = mImageView.getViewTreeObserver();
        vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                mImageView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                finalHeight = mImageView.getMeasuredHeight();
                finalWidth = mImageView.getMeasuredWidth();
                makeSpan();
            }
        });
    }
}

This code can be improved.
I am using a very simple (and raw) float textLineHeight = mTextView.getPaint().getTextSize(); to calculate the number of lines.
You can add paddings, margins or you can use a Rect to calculate the text bounds.

  /**
     * This method builds the text layout
     */
    private void makeSpan() {

        /**
         * Get the text
         */
        String plainText=getResources().getString(R.string.text_sample);
        

        int allTextStart = 0;
        int allTextEnd = htmlText.length() - 1;

        /**
         * Calculate the lines number = image height.
         * You can improve it... it is just an example
         */
        int lines;
        Rect bounds = new Rect();
        mTextView.getPaint().getTextBounds(plainText.substring(0,10), 0, 1, bounds);

        //float textLineHeight = mTextView.getPaint().getTextSize();
        float fontSpacing=mTextView.getPaint().getFontSpacing();
        lines = (int) (finalHeight/fontSpacing);

        /**
         * Build the layout with LeadingMarginSpan2
         */
        MyLeadingMarginSpan2 span = new MyLeadingMarginSpan2(lines, finalWidth +10 );
        mSpannableString.setSpan(span, allTextStart, allTextEnd,
                   Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

        mTextView.setText(mSpannableString);
    }



You can get code from GitHub:


19 Mar 2014

Android using Analog Clock and Digital Clock

An Android Analog and Digital Clock widgets are used to display Clock in Analog and Digital format. Since the DigitalClock package is deprecated we are going to use TextClock to display Digital Clock.


Creating Project:

Make sure you have properly setup the Android SDK, AVD for Testing the Application. Create a New project in Eclipse IDE with the package as “com.learn2crack.clock“. Create the Main Activity as “MainActivity” and the main Layout as “activity_main“.

Creating Layout:

The Main layout for our project is “activity_main” which has a Button widget to switch between AnalogClock and TextClock widgets.

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >
     <TextView
        android:id="@+id/welcome"
        android:layout_gravity="center"
        android:textSize="20sp"
        android:text="Android Clock"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
     <Button
        android:id="@+id/btn"
        android:layout_gravity="center"
        android:textSize="20sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextClock
        android:id="@+id/clock"
        android:layout_gravity="center"
        android:textSize="40sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
    <AnalogClock
        android:id="@+id/aclock"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
</LinearLayout>


Creating Activity:

First we are importing the TextClock and AnalogClock. When the button is pressed it hides one widget and enables other widget.

MainActivity.java


import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextClock;
import android.widget.AnalogClock;
import android.app.Activity;
public class MainActivity extends Activity {
  TextClock clock;
  AnalogClock aclock;
  Button btn;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    clock = (TextClock)findViewById(R.id.clock);
    aclock = (AnalogClock)findViewById(R.id.aclock);
    btn = (Button)findViewById(R.id.btn);
    btn.setText("Show Analog Clock");
    aclock.setVisibility(View.INVISIBLE);
      btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View arg0) {
      // TODO Auto-generated method stub
      btn.setText("Show Digital Clock");
      aclock.setVisibility(View.VISIBLE);
      clock.setVisibility(View.INVISIBLE);
      btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View arg0) {
          // TODO Auto-generated method stub
        onCreate(null);
        }
      });
    }
  });
  }
}




Creating Manifest:

No other special Permissions are required for our project.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
    package="com.learn2crack.clock"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk
        android:minSdkVersion="17"
        android:targetSdkVersion="18" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.learn2crack.clock.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>



Screenshots:











Finally run the project in the Emulator.
Enjoy :)
Any questions comment here.