Android example source code file (CheckedTextView.java)

This example Android source code file (CheckedTextView.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, attributeset, checkable, checked_state_set, checkedtextview, content, drawable, drawing, graphics, override, paint, typedarray, ui, view, visible

The CheckedTextView.java Android example source code

/*
 * 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 android.widget;

import com.android.internal.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.ViewDebug;
import android.view.accessibility.AccessibilityEvent;


/**
 * An extension to TextView that supports the {@link android.widget.Checkable} interface.
 * This is useful when used in a {@link android.widget.ListView ListView} where the it's 
 * {@link android.widget.ListView#setChoiceMode(int) setChoiceMode} has been set to
 * something other than {@link android.widget.ListView#CHOICE_MODE_NONE CHOICE_MODE_NONE}.
 *
 */
public class CheckedTextView extends TextView implements Checkable {
    private boolean mChecked;
    private int mCheckMarkResource;
    private Drawable mCheckMarkDrawable;
    private int mBasePaddingRight;
    private int mCheckMarkWidth;

    private static final int[] CHECKED_STATE_SET = {
        R.attr.state_checked
    };

    public CheckedTextView(Context context) {
        this(context, null);
    }

    public CheckedTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

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

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.CheckedTextView, defStyle, 0);

        Drawable d = a.getDrawable(R.styleable.CheckedTextView_checkMark);
        if (d != null) {
            setCheckMarkDrawable(d);
        }

        boolean checked = a.getBoolean(R.styleable.CheckedTextView_checked, false);
        setChecked(checked);

        a.recycle();
    }

    public void toggle() {
        setChecked(!mChecked);
    }

    @ViewDebug.ExportedProperty
    public boolean isChecked() {
        return mChecked;
    }

    /**
     * <p>Changes the checked state of this text view.

     *
     * @param checked true to check the text, false to uncheck it
     */
    public void setChecked(boolean checked) {
        if (mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();
        }
    }


    /**
     * Set the checkmark to a given Drawable, identified by its resourece id. This will be drawn
     * when {@link #isChecked()} is true.
     * 
     * @param resid The Drawable to use for the checkmark.
     */
    public void setCheckMarkDrawable(int resid) {
        if (resid != 0 && resid == mCheckMarkResource) {
            return;
        }

        mCheckMarkResource = resid;

        Drawable d = null;
        if (mCheckMarkResource != 0) {
            d = getResources().getDrawable(mCheckMarkResource);
        }
        setCheckMarkDrawable(d);
    }

    /**
     * Set the checkmark to a given Drawable. This will be drawn when {@link #isChecked()} is true.
     *
     * @param d The Drawable to use for the checkmark.
     */
    public void setCheckMarkDrawable(Drawable d) {
        if (mCheckMarkDrawable != null) {
            mCheckMarkDrawable.setCallback(null);
            unscheduleDrawable(mCheckMarkDrawable);
        }
        if (d != null) {
            d.setCallback(this);
            d.setVisible(getVisibility() == VISIBLE, false);
            d.setState(CHECKED_STATE_SET);
            setMinHeight(d.getIntrinsicHeight());
            
            mCheckMarkWidth = d.getIntrinsicWidth();
            mPaddingRight = mCheckMarkWidth + mBasePaddingRight;
            d.setState(getDrawableState());
        } else {
            mPaddingRight = mBasePaddingRight;
        }
        mCheckMarkDrawable = d;
        requestLayout();
    }
    
    @Override
    public void setPadding(int left, int top, int right, int bottom) {
        super.setPadding(left, top, right, bottom);
        mBasePaddingRight = mPaddingRight;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final Drawable checkMarkDrawable = mCheckMarkDrawable;
        if (checkMarkDrawable != null) {
            final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK;
            final int height = checkMarkDrawable.getIntrinsicHeight();

            int y = 0;

            switch (verticalGravity) {
                case Gravity.BOTTOM:
                    y = getHeight() - height;
                    break;
                case Gravity.CENTER_VERTICAL:
                    y = (getHeight() - height) / 2;
                    break;
            }
            
            int right = getWidth();
            checkMarkDrawable.setBounds(
                    right - mCheckMarkWidth - mBasePaddingRight, 
                    y, 
                    right - mBasePaddingRight, 
                    y + height);
            checkMarkDrawable.draw(canvas);
        }
    }
    
    @Override
    protected int[] onCreateDrawableState(int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        }
        return drawableState;
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        
        if (mCheckMarkDrawable != null) {
            int[] myDrawableState = getDrawableState();
            
            // Set the state of the Drawable
            mCheckMarkDrawable.setState(myDrawableState);
            
            invalidate();
        }
    }

    @Override
    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        boolean populated = super.dispatchPopulateAccessibilityEvent(event);
        if (!populated) {
            event.setChecked(mChecked);
        }
        return populated;
    }
}