自定义view实现手动签名

直接看代码就行了。

自定义得view

public class CustomView extends View {
    private Path path = new Path();
    private float prex;
    private float prey;

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

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                path.moveTo(event.getX(), event.getY());
                prex = event.getX();
                prey = event.getY();
                return true;

            case MotionEvent.ACTION_MOVE:
                path.lineTo(event.getX(), event.getY());
                invalidate();
            default:
                break;
        }
        return super.onTouchEvent(event);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setStrokeWidth(20); //设置线得粗细大小
        paint.setColor(Color.RED);
        paint.setStyle(Paint.Style.STROKE);
        canvas.drawPath(path,paint);
    }

    /**
     * 清除路径
     */
    public void reset(){
        path.reset();
        invalidate();
    }
}

然后是布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_clear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <com.example.customview.CustomView
        android:id="@+id/cus_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

然后是我们得activity

public class MainActivity extends AppCompatActivity {
    private CustomView customView;
    private Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        customView = findViewById(R.id.cus_view);
        btn = findViewById(R.id.btn_clear);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                customView.reset();
            }
        });
    }
}

ok，非常easy。