[Android] Touch 拖移元件－Saioyan梟夜

示範

XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/ig1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@mipmap/ic_launcher" />

    <TextView
        android:id="@+id/t1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toTopOf="@+id/ig1"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

JAVA

public class MainActivity extends AppCompatActivity implements View.OnTouchListener{
    ImageView ig1;
    TextView t1;
    double touchx,touchy;
    int mx,my;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
ig1=(ImageView)findViewById(R.id.ig1);
        t1=(TextView) findViewById(R.id.t1);
        ig1.setOnTouchListener(this);
    }
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (v.getId()) {
            case R.id.ig1:
                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:
                        touchx = event.getX();
                        touchy = event.getY()+210;
                        t1.setText(""+touchy);
                    case MotionEvent.ACTION_MOVE:
                        mx = (int) (event.getRawX() - touchx);
                        my = (int) (event.getRawY() - touchy);
                        ig1.layout(mx,my,ig1.getWidth()+mx,ig1.getHeight()+my);
                    case MotionEvent.ACTION_UP:
                }}
        return true;
    }
}