Checkable ImageView

Does anybody know if it possible to make ImageView checkable. I try to use State-list drawable resource in my project where I define pictures for my ImageView check states, but there is no property to make ImageView checkable, only clickable.

Maybe 开发者_开发问答anybody knows a way to solve this problem?

Use this custom ImageView implementation (taken from here) :

public class CheckableImageView extends ImageView implements Checkable {
    private boolean mChecked;

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

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

    @Override
    public int[] onCreateDrawableState(final int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked())
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        return drawableState;
    }

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

    @Override
    public boolean isChecked() {
        return mChecked;
    }

    @Override
    public void setChecked(final boolean checked) {
        if (mChecked == checked)
            return;
        mChecked = checked;
        refreshDrawableState();
    }
}

EDIT: Updated, Kotlin solution:

class CheckableImageView : AppCompatImageView, Checkable {
    private var mChecked = false

    constructor(context: Context) : super(context) {}
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {}
    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {}

    override fun onCreateDrawableState(extraSpace: Int): IntArray {
        val drawableState = super.onCreateDrawableState(extraSpace + 1)
        if (isChecked) mergeDrawableStates(drawableState, CHECKED_STATE_SET)
        return drawableState
    }

    override fun toggle() {
        isChecked = !mChecked
    }

    override fun isChecked(): Boolean {
        return mChecked
    }

    override fun setChecked(checked: Boolean) {
        if (mChecked == checked) return
        mChecked = checked
        refreshDrawableState()
    }

    companion object {
        private val CHECKED_STATE_SET = intArrayOf(android.R.attr.state_checked)
    }
}

Instead of making an ImageView checkable you can set a state list drawable as background for a checkbox which will automatically flip the images.

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_checkable="true" android:drawable="@drawable/icon_pressed" /> <!-- pressed -->
    <item android:state_checked="true" android:drawable="@drawable/icon_focused" /> <!-- focused -->
    <item android:drawable="@drawable/icon_default" /> <!-- default -->
</selector>

I implements OnClickListener from android developer's code for direct checking.

public class CheckableImageView extends ImageView implements Checkable, View.OnClickListener {
    private boolean mChecked;

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

    public CheckableImageView(final Context context, final AttributeSet attrs) {
        super(context, attrs);

        setOnClickListener(this);
    }

    @Override
    public int[] onCreateDrawableState(final int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked())
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        return drawableState;
    }

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

    @Override
    public boolean isChecked() {
        return mChecked;
    }

    @Override
    public void setChecked(final boolean checked) {
        if (mChecked == checked)
            return;
        mChecked = checked;
        refreshDrawableState();
    }

    @Override
    public void onClick(View v) {
      toggle();
    }
}

If you want change check state while clicking on ImageView, change "extend ImageView" to CompoundButton.

public class CheckableImageView extends CompoundButton {

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

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

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

    public void setChecked(boolean b) {
        boolean oldState = isChecked();
        super.setChecked(b);
        if (b != oldState) {
            refreshDrawableState();
        }
    }

    @Override
    public int[] onCreateDrawableState(int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(drawableState, CheckedStateSet);
        }
        return drawableState;
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        invalidate();
    }

}

this what i used in my app

public class MainActivity extends Activity implements OnClickListener {

private boolean paused = false;  

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

        switch (v.getId()) {

            case R.id.imageview_pause:

                paused = !paused;

                if (paused) {

                    btn_pause.setBackgroundResource(R.drawable.pause_key_pressed);

                }else{

                    btn_pause.setBackgroundResource(R.drawable.pause_key);
                }

                break;
        }
}
}