动态更改ActionBar中的图标

Question

我有一个Activity它有一个ActionBar,但我需要改变的图标ActionBar动态,我有一个暂停和播放按钮,我需要更换播放与按钮暂停按钮就可以了用户点击.我搜索过,发现它:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    if(DEBUG) Log.i("onCreateOptionsMenu()", "onCreateOptionsMenu() -> LogicAnalizerView");
    //menu.add("").setIcon(R.drawable.pause).setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.actionbarlogic, menu);
    menu.removeItem(R.id.pauseLogic);

    return true;
}

因此,通过这种方式,我删除了暂停按钮,我也可以添加它,但它只会在我启动Activity并且ActionBar绘制时发生.我怎么强迫重绘ActionBar？此外,通过这种方式,整个ActionBar重绘.是对的吗？有没有办法只重绘我想要的按钮/图标？

谢谢 :)

Answer 1

在完成通货膨胀后,您必须保存对MenuItem的引用.如下所示:

public boolean onCreateOptionsMenu( Menu menu ) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate( R.menu.actionbarlogic, menu );
    playMenu = menu.findItem(R.id.playMenu);
    updatePlayStatus();
    return menu;
}

public void updatePlayStatus() {
    if( playService.isConnected() ) {
        playService.isPlaying() ? playMenu.setIcon(R.drawable.pause) : playMenu.setIcon(R.drawable.play);
    }
}

然后你可以随时参考playMenu.因此,您可以修改项目,如播放器完成播放,并应返回播放图标.

Answer 2

您可以隐藏不想显示的按钮,而不是删除它们.

例如:

private boolean isPlaying;
MenuItem mPlayMenuItem;
MenuItem mPauseMenuItem;

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu items for use in the action bar
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.actionbarlogic, menu);

    mPlayMenuItem = menu.findItem(R.id.action_play);
    mPauseMenuItem = menu.findItem(R.id.action_pause);

    return super.onCreateOptionsMenu(menu);

}

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    switch (item.getItemId()) {
        case R.id.action_play:
            isPlaying = true;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                this.invalidateOptionsMenu();
            }
            return true;
        case R.id.action_pause:
            isPlaying = false;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                this.invalidateOptionsMenu();
            }
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}


 @Override
public boolean onPrepareOptionsMenu (Menu menu) {
    super.onPrepareOptionsMenu(menu);

    if (isPlaying) {
        mPlayMenuItem.setVisible(false); // hide play button
        mPauseMenuItem.setVisible(true); // show the pause button
    } else if (!isPlaying) {
        mPlayMenuItem.setVisible(true); // show play button
        mPauseMenuItem.setVisible(false); // hide the pause button
    }

    return true;
}

请注意,这个:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
     this.invalidateOptionsMenu();
}

需要更新操作栏.在3.0设备之后,操作栏不会自动更新.因此,您必须手动告诉它调用"OnPrepareOptionsMenu(Menu)",以便它通过调用"Activity.invalidateOptionsMenu()"来刷新项目.

希望这可以帮助!

参考:http://developer.android.com/reference/android/app/Activity.html#onPrepareOptionsMenu(android.view.Menu)

http://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#invalidateOptionsMenu(android.app.Activity)

Answer 3

private Menu mMenu;

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main_activity, menu);

    // Save the menu reference
    mMenu = menu;
    return super.onCreateOptionsMenu(menu);
}

// For example - Call when you need to change icon
private void setActionIcon(boolean showWithBadge)
{
    MenuItem item = mMenu.findItem(R.id.ITEM_ID);

    if(mMenu != null)
    {
        if(showWithBadge)
        {
            item.setIcon(R.drawable.IC_WITH_BADGE);           
        }
        else 
        {
            item.setIcon(R.drawable.IC_WITHOUT_BADGE);
        }
    }
}