How to add custom view to the layout?

Question

I have a GraphicsView class that extends from the View class and I want to add this GraphicsView class to the main layout in my project. How can I do that?

static public class GraphicsView extends View {
        public GraphicsView(Context context) {
        super(context);
        }
        @Override
        protected void onDraw(Canvas canvas) {
        // Drawing commands go here
            Path rect = new  Path();
            rect.addRect(100, 100, 250, 50, Direction.CW);
            Paint cPaint = new Paint();
            cPaint.setColor(Color.LTGRAY); 
            canvas.drawPath(rect, cPaint);
        }
    }

and my main.xml:

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

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <TextView 
        android:id="@+id/Customfont"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

     <View 
         android:id="@+id/view"
          android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

Answer 1

This is working for me and add the view in XML with full path and try giving wrapcontent for height and width.

public class RectangleView extends View {
    public RectangleView(Context context) {
        super(context);
    }

    public RectangleView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RectangleView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setColor(Color.GRAY);
        canvas.drawColor(Color.BLUE);
        canvas.drawRect(10,10,50,50, paint);
    }
}

Answer 2

i finaly got it here is the code the XML code

<com.customfonts.namespace.BreakDownBar
         android:id="@+id/gview"
          android:layout_width="fill_parent"
        android:layout_height="20dip"
        android:layout_marginLeft="10dip"
        android:layout_marginRight="10dip"
        android:background="@color/BreakDownBarBack"/>

and the class

package com.customfonts.namespace;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.util.AttributeSet;
import android.view.View;



public class BreakDownBar extends View {

    public BreakDownBar(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

        @Override
        protected void onDraw(Canvas canvas) {
                //Draw rectangle;
                Path rect = new  Path();
                rect.addRect(0, 0,250, 150,Direction.CW);
                Paint cpaint = new Paint();
                cpaint.setColor(Color.GREEN); 
                canvas.drawPath(rect, cpaint);
        }
}

Answer 3

Because your custom View is an inner class in your Activity the java compiler will output the name ActivityName$GraphicsView for that class. You can't use that name directly as the View name in the xml layout because of the $ character but you can do it like this:

 <view 
    class="com.package.here.ActivityName$GraphicsView"
    android:id="@+id/view"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>

where ActivityName is the name of the activity where your GraphicsView class is declared.

Answer 4

If I remember correctly, you need to provide more constructors to use view from xml file (add it to xml file like "Me and We" suggested).

public GraphicsView(Context context) {
    super(context);
}

public GraphicsView(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public GraphicsView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

Update: fixed code.

Answer 5

public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    LinearLayout v = (LinearLayout) findViewById(R.id.linearLayout);
    MyGraphics myView = new MyGraphics(this);
    v.addView(myView);
}
}


public class MyGraphics extends View {
public MyGraphics(Context context) {
    super(context);
}

@Override
protected void onDraw(Canvas canvas) {
    // Drawing commands go here
    Path rect = new Path();
    rect.addRect(100, 100, 250, 50, Direction.CW);
    Paint cPaint = new Paint();
    cPaint.setColor(Color.LTGRAY);
    canvas.drawPath(rect, cPaint);
}


}

XML:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" 
android:id="@+id/linearLayout">

<TextView 
    android:id="@+id/Customfont"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello" />


</LinearLayout>

Answer 6

You need to give complete path of your class that extends View,

<com.blah.blah.GraphicsView
         android:id="@+id/view"
          android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

Answer 7

you need to do this:

LinearLayout v = (LinearView) findViewById(R.id.linnnnlayout);
GraphicsView myView = new myGraphicsView(this);
v.addView(myView);