写一个Android输入法02——候选窗、转换

    public CandidateView(Context context) {
        super(context);
        Log.d(this.getClass().toString(), "CandidateView: ");

        // 设置前景、背景色、字体、字号
        Resources r = context.getResources();

        setBackgroundColor(getResources().getColor(R.color.candidate_background, null));

        mColorNormal = r.getColor(R.color.candidate_normal, null);
        mVerticalPadding = r.getDimensionPixelSize(R.dimen.candidate_vertical_padding);

        mPaint = new Paint();
        mPaint.setColor(mColorNormal);
        mPaint.setAntiAlias(true);
        mPaint.setTextSize(r.getDimensionPixelSize(R.dimen.candidate_font_height));
        mPaint.setStrokeWidth(0);

        setWillNotDraw(false);  // 覆盖了onDraw函数应清除该标记
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.d(this.getClass().toString(), "onMeasure: ");
        int wMode = MeasureSpec.getMode(widthMeasureSpec);
        int wSize = MeasureSpec.getSize(widthMeasureSpec);

        int measuredWidth = resolveSize(50, widthMeasureSpec);

        final int desiredHeight = ((int)mPaint.getTextSize()) + mVerticalPadding;

        // 系统会根据返回值确定窗体的大小
        setMeasuredDimension(measuredWidth, resolveSize(desiredHeight, heightMeasureSpec));
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Log.d(this.getClass().toString(), "onDraw: ");
        super.onDraw(canvas);

        if (mSuggestions == null)
            return;

        // 依次绘制每组候选字串
        int x = 0;
        final int count = mSuggestions.size();
        final int height = getHeight();
        final int y = (int) (((height - mPaint.getTextSize()) / 2) - mPaint.ascent());

        for (int i = 0; i < count; i++) {
            String suggestion = mSuggestions.get(i);
            float textWidth = mPaint.measureText(suggestion);
            final int wordWidth = (int) textWidth + X_GAP * 2;

            canvas.drawText(suggestion, x + X_GAP, y, mPaint);
            x += wordWidth;
        }
    }

    public void setSuggestions(List<String> suggestions) {
        // 设置候选字串列表
        if (suggestions != null) {
            mSuggestions = new ArrayList<String>(suggestions);
        }
        invalidate();
        requestLayout();
    }

}

public class AndroidXXIME extends InputMethodService
        implements KeyboardView.OnKeyboardActionListener {
……

    @Override public View onCreateCandidatesView(){
        Log.d(this.getClass().toString(), "onCreateCandidatesView: ");
        candidateView = new CandidateView(this);
        return candidateView;
    }
……
}

public class AndroidXXIME extends InputMethodService
        implements KeyboardView.OnKeyboardActionListener {
……
    @Override
    public void onKey(int primaryCode, int[] keyCodes) {
        InputConnection ic = getCurrentInputConnection();
        playClick(primaryCode);
        switch(primaryCode){
            case Keyboard.KEYCODE_DELETE :
                // 如果收到的是DELETE键，则删除光标前的一个字符
                ic.deleteSurroundingText(1, 0);
                break;
            case Keyboard.KEYCODE_DONE:
                // 如果收到的是DONE键，则执行回车
                ic.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_ENTER));
                break;
            default:
                char code = (char)primaryCode;
                if(code == ‘ ‘){ // 如果收到的是空格
                    if(m_composeString.length() > 0) {  // 如果有写作串，则将首个候选提交上屏
                        ic.commitText(m_composeString, m_composeString.length());
                        m_composeString.setLength(0);
                    }else{                              // 如果没有写作串，则直接将空格上屏
                        ic.commitText(" ", 1);
                    }
                }else {          // 否则，将字符计入写作串
                    m_composeString.append(code);
                    ic.setComposingText(m_composeString, 1);
                }
                updateCandidates();
        }
    }
}