Android記錄單點和多點觸控的位置

原創

2020-02-22 18:13

爲了完成可以記錄滑動和縮放的位置信息，嘗試了包括GestureDector類和OnTouchListener類，雖然能夠很好的識別具體手勢，可是在區分單點還是多點觸控方面還是有些欠缺。

本文對TextView進行監聽，在position中顯示記錄觸控的痕跡。

tv = (TextView)findViewById(R.id.textv);
position = (TextView)findViewById(R.id.position);

通過對event.getPointerCount()來對點的數目進行判斷

通過ACYION_POINTER_DOWN對第二個點進行記錄，同時記得用這個參數時要配合ACTION_MASK在switch語句中

tv.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()& MotionEvent.ACTION_MASK){
                    case MotionEvent.ACTION_DOWN:
                        position.setText("N1S"+" ("+<span style="font-family: Arial, Helvetica, sans-serif;">event.getX()</span><span style="font-family: Arial, Helvetica, sans-serif;">+" , "+</span><span style="font-family: Arial, Helvetica, sans-serif;">event.getY()</span><span style="font-family: Arial, Helvetica, sans-serif;">+")");</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span>                        break;
                    case MotionEvent.ACTION_POINTER_DOWN:
                        position.append("N2S"+" ("+<span style="font-family: Arial, Helvetica, sans-serif;">event.getX()</span><span style="font-family: Arial, Helvetica, sans-serif;">+" , "+</span><span style="font-family: Arial, Helvetica, sans-serif;">event.getY()</span><span style="font-family: Arial, Helvetica, sans-serif;">+")");</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span>                        break;
                    case MotionEvent.ACTION_MOVE:
                        if(event.getPointerCount()<2 ){
                        position.append("M" + " (" + event.getX() + " , " + event.getY() + ")");}
                        else{
                            position.append("TM"+" (" + event.getX(0) + " , " + event.getY(0) + ")"
                                    +" (" + event.getX(1) + " , " + event.getY(1) + ")");
                        }
                }
                return true;
            }
        });