java – 使用自定义方法绘制到画布？

目前,在我的包中,我有一个绘制画布实例的线程.我正在从资源中绘制Drawable位图.我想做的是让线程处理背景图像的绘制.但是,自定义对象的实例可以使用可绘制对象绘制到同一个画布.这在逻辑上似乎是可能的,但我无法让它工作.每当我尝试检索自定义类中的资源时,应用程序在启动时崩溃.

以下是我的一些努力:(如果我做了一些愚蠢的事情,请不要笑,我正在努力.)

public class Worker{

//Get drawables
//  Resources res = getResources();
//  Drawable man1 = res.getDrawable(R.drawable.workertest);


//  Context mContext;
//  Resources res = mContext.getResources();

//  Drawable man1 = mContext.getResources().getDrawable(R.drawable.workertest);
//  Drawable man2 = mContext.getResources().getDrawable(R.drawable.workertest1);

//  Drawable man1 = res.getDrawable(R.drawable.workertest);
//  Drawable man2 = res.getDrawable(R.drawable.workertest1);

}

正如你所看到的,我尝试了几种不同的方法,并且我也尝试过(扩展活动)添加到我的班级,但我无法弄清楚这一点.

这段代码并没有解决实际绘制到画布的问题,我还没有跨过那座桥

编辑：这是活动.如你所见,它在月球视图中调用一个线程.该线程实例化需要检索Drawable的对象.如何以神的名义获取对象的应用程序上下文？还是有其他办法吗？是的,这是来自android示例代码的代码.

public class LunarLander extends Activity {
    private static final int MENU_EASY = 1;

    private static final int MENU_HARD = 2;

    private static final int MENU_MEDIUM = 3;

    private static final int MENU_PAUSE = 4;

    private static final int MENU_RESUME = 5;

    private static final int MENU_START = 6;

    private static final int MENU_STOP = 7;


    /** A handle to the thread that's actually running the animation. */
    public static LunarThread mLunarThread;

    /** A handle to the View in which the game is running. */
    public LunarView mLunarView;



    /**
     * Invoked during init to give the Activity a chance to set up its Menu.
     *
     * @param menu the Menu to which entries may be added
     * @return true
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        menu.add(0,MENU_START,R.string.menu_start);
        menu.add(0,MENU_STOP,R.string.menu_stop);
        menu.add(0,MENU_PAUSE,R.string.menu_pause);
        menu.add(0,MENU_RESUME,R.string.menu_resume);
        menu.add(0,MENU_EASY,R.string.menu_easy);
        menu.add(0,MENU_MEDIUM,R.string.menu_medium);
        menu.add(0,MENU_HARD,R.string.menu_hard);

        return true;
    }

    /**
     * Invoked when the user selects an item from the Menu.
     *
     * @param item the Menu entry which was selected
     * @return true if the Menu item was legit (and we consumed it),false
     *         otherwise
     */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case MENU_START:
                mLunarThread.doStart();
                return true;
            case MENU_STOP:
                mLunarThread.setState(LunarThread.STATE_LOSE,getText(R.string.message_stopped));
                return true;
            case MENU_PAUSE:
                mLunarThread.pause();
                return true;
            case MENU_RESUME:
                mLunarThread.unpause();
                return true;
            case MENU_EASY:
                mLunarThread.setDifficulty(LunarThread.DIFFICULTY_EASY);
                return true;
            case MENU_MEDIUM:
                mLunarThread.setDifficulty(LunarThread.DIFFICULTY_MEDIUM);
                return true;
            case MENU_HARD:
                mLunarThread.setDifficulty(LunarThread.DIFFICULTY_HARD);
                return true;
        }

        return false;
    }

    /**
     * Invoked when the Activity is created.
     *
     * @param savedInstanceState a Bundle containing state saved from a previous
     *        execution,or null if this is a new execution
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // tell system to use the layout defined in our XML file
        setContentView(R.layout.lunar_layout);

        // get handles to the LunarView from XML,and its LunarThread
        mLunarView = (LunarView) findViewById(R.id.lunar);
        mLunarThread = mLunarView.getThread();


        // give the LunarView a handle to the TextView used for messages
        mLunarView.setTextView((TextView) findViewById(R.id.text));




        if (savedInstanceState == null) {
            // we were just launched: set up a new game
            mLunarThread.setState(LunarThread.STATE_READY);
            Log.w(this.getClass().getName(),"SIS is null");
        } else {
            // we are being restored: resume a previous game
            mLunarThread.restoreState(savedInstanceState);
            Log.w(this.getClass().getName(),"SIS is nonnull");
        }
    }

    /**
     * Invoked when the Activity loses user focus.
     */
    @Override
    protected void onPause() {
        super.onPause();
        mLunarView.getThread().pause(); // pause game when Activity pauses
    }

    /**
     * Notification that something is about to happen,to give the Activity a
     * chance to save state.
     *
     * @param outState a Bundle into which this Activity should save its state
     */
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        // just have the View's thread save its state into our Bundle
        super.onSaveInstanceState(outState);
        mLunarThread.saveState(outState);
        Log.w(this.getClass().getName(),"SIS called");
    }
    public boolean onTouchEvent(MotionEvent event){
        int clickX = Math.round(event.getX()/10)*10;
        int clickY = Math.round(event.getY()/10)*10;

        LunarView.xCo = clickX;
        LunarView.yCo = clickY;

        return true;

    }