1 protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)

1 protected void onLayout (boolean changed, int left, int top, int right, int bottom)

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.view;

// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import com.example.android.apis.R;


/**
 * Example of how to write a custom subclass of View. LabelView
 * is used to draw simple text views. Note that it does not handle
 * styled text or right-to-left writing systems.
 *
 */
public class LabelView extends View {
    private Paint mTextPaint;
    private String mText;
    private int mAscent;
    
    /**
     * Constructor.  This version is only needed if you will be instantiating
     * the object manually (not from a layout XML file).
     * @param context
     */
    public LabelView(Context context) {
        super(context);
        initLabelView();
    }

    /**
     * Construct object, initializing with any attributes we understand from a
     * layout file. These attributes are defined in
     * SDK/assets/res/any/classes.xml.
     * 
     * @see android.view.View#View(android.content.Context, android.util.AttributeSet)
     */
    public LabelView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initLabelView();

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.LabelView);

        CharSequence s = a.getString(R.styleable.LabelView_text);
        if (s != null) {
            setText(s.toString());
        }

        // Retrieve the color(s) to be used for this view and apply them.
        // Note, if you only care about supporting a single color, that you
        // can instead call a.getColor() and pass that to setTextColor().
        setTextColor(a.getColor(R.styleable.LabelView_textColor, 0xFF000000));

        int textSize = a.getDimensionPixelOffset(R.styleable.LabelView_textSize, 0);
        if (textSize > 0) {
            setTextSize(textSize);
        }

        a.recycle();
    }

    private final void initLabelView() {
        mTextPaint = new Paint();
        mTextPaint.setAntiAlias(true);
        // Must manually scale the desired text size to match screen density
        mTextPaint.setTextSize(16 * getResources().getDisplayMetrics().density);
        mTextPaint.setColor(0xFF000000);
        setPadding(3, 3, 3, 3);
    }

    /**
     * Sets the text to display in this label
     * @param text The text to display. This will be drawn as one line.
     */
    public void setText(String text) {
        mText = text;
        requestLayout();
        invalidate();
    }

    /**
     * Sets the text size for this label
     * @param size Font size
     */
    public void setTextSize(int size) {
        // This text size has been pre-scaled by the getDimensionPixelOffset method
        mTextPaint.setTextSize(size);
        requestLayout();
        invalidate();
    }

    /**
     * Sets the text color for this label.
     * @param color ARGB value for the text
     */
    public void setTextColor(int color) {
        mTextPaint.setColor(color);
        invalidate();
    }

    /**
     * @see android.view.View#measure(int, int)
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(measureWidth(widthMeasureSpec),
                measureHeight(heightMeasureSpec));
    }

    /**
     * Determines the width of this view
     * @param measureSpec A measureSpec packed into an int
     * @return The width of the view, honoring constraints from measureSpec
     */
    private int measureWidth(int measureSpec) {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        if (specMode == MeasureSpec.EXACTLY) {
            // We were told how big to be
            result = specSize;
        } else {
            // Measure the text
            result = (int) mTextPaint.measureText(mText) + getPaddingLeft()
                    + getPaddingRight();
            if (specMode == MeasureSpec.AT_MOST) {
                // Respect AT_MOST value if that was what is called for by measureSpec
                result = Math.min(result, specSize);
            }
        }

        return result;
    }

    /**
     * Determines the height of this view
     * @param measureSpec A measureSpec packed into an int
     * @return The height of the view, honoring constraints from measureSpec
     */
    private int measureHeight(int measureSpec) {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        mAscent = (int) mTextPaint.ascent();
        if (specMode == MeasureSpec.EXACTLY) {
            // We were told how big to be
            result = specSize;
        } else {
            // Measure the text (beware: ascent is a negative number)
            result = (int) (-mAscent + mTextPaint.descent()) + getPaddingTop()
                    + getPaddingBottom();
            if (specMode == MeasureSpec.AT_MOST) {
                // Respect AT_MOST value if that was what is called for by measureSpec
                result = Math.min(result, specSize);
            }
        }
        return result;
    }

    /**
     * Render the text
     * 
     * @see android.view.View#onDraw(android.graphics.Canvas)
     */
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent, mTextPaint);
    }
}

 1     public class Test extends Activity {  
 2      private LinearLayout mBackgroundLayout;  
 3      private TextViewTest mTextViewTest;  
 4       
 5      /** Called when the activity is first created. */  
 6      @Override  
 7      public void onCreate(Bundle savedInstanceState) {  
 8       super.onCreate(savedInstanceState);  
 9       
10       mBackgroundLayout = new MyLayout(this);  
11       mBackgroundLayout.setLayoutParams(new LinearLayout.LayoutParams(  
12         LinearLayout.LayoutParams.FILL_PARENT,  
13         LinearLayout.LayoutParams.FILL_PARENT));  
14       
15       mTextViewTest = new TextViewTest(this);  
16       
17       mBackgroundLayout.addView(mTextViewTest);  
18       setContentView(mBackgroundLayout);  
19      }  
20      public class MyLayout extends LinearLayout{  
21       
22       public MyLayout(Context context) {  
23        super(context);  
24        // TODO Auto-generated constructor stub  
25       }  
26       
27       @Override  
28       protected void onLayout(boolean changed, int l, int t, int r, int b) {  
29        // TODO Auto-generated method stub  
30        super.onLayout(changed, l, t, r, b);  
31        Log.i("Tag", "--------------");  
32        View mView=getChildAt(0);  
33        mView.measure(0, 0);  
34       }  
35         
36      }  
37      public class TextViewTest extends TextView {  
38       public TextViewTest(Context context) {  
39        super(context);  
40        // TODO Auto-generated constructor stub  
41        setText("test test ");  
42       }  
43         
44       @Override  
45        protected void onDraw(Canvas canvas) {  
46        // TODO Auto-generated method stub  
47        super.onDraw(canvas);  
48        // measure(0, 0);  
49        Log.i("Tag", "width: " + getWidth() + ",height: " + getHeight());  
50        Log.i("Tag", "MeasuredWidth: " + getMeasuredWidth()  
51          + ",MeasuredHeight: " + getMeasuredHeight());  
52        }  
53       
54      }  
55     }  

 1     public class Test extends Activity {  
 2      private TextViewTest mTextViewTest;  
 3       
 4      /** Called when the activity is first created. */  
 5      @Override  
 6      public void onCreate(Bundle savedInstanceState) {  
 7       super.onCreate(savedInstanceState);  
 8       mTextViewTest = new TextViewTest(this);  
 9       setContentView(mTextViewTest);  
10      }  
11       
12      public class TextViewTest extends TextView {  
13       public TextViewTest(Context context) {  
14        super(context);  
15        // TODO Auto-generated constructor stub  
16        setText("test test ");  
17       }  
18       
19       @Override  
20       protected void onDraw(Canvas canvas) {  
21        // TODO Auto-generated method stub  
22        super.onDraw(canvas);  
23        measure(0, 0);  
24        Log.i("Tag", "width: " + getWidth() + ",height: " + getHeight());  
25        Log.i("Tag", "MeasuredWidth: " + getMeasuredWidth()  
26          + ",MeasuredHeight: " + getMeasuredHeight());  
27       }  
28      }  
29     }