【发布时间】：2016-09-25 14:28:49
【问题描述】：
我是 android 新手。现在我正在使用三个按钮创建拖放功能。我确实检查了拖动按钮不应该为空，因为我必须从该按钮获取数据并且放置按钮应该为空。
如何将按钮移动到仅靠按钮附近？如果 b1,b2,b3 水平存在意味着 b1 必须移动 b2，但可以移动两侧，b3 必须移动 b2 侧只有。我的代码在这里。请指导我。
import android.content.ClipData;
import android.graphics.Canvas;
import android.graphics.Point;
import android.graphics.drawable.ColorDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.DragEvent;
import android.view.View;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
Button b1,b2,b3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button) findViewById(R.id.b1);
b2 = (Button) findViewById(R.id.b2);
b3 = (Button) findViewById(R.id.b3);
findViewById(R.id.b1).setOnLongClickListener(longClickListener);
findViewById(R.id.b2).setOnLongClickListener(longClickListener);
findViewById(R.id.b3).setOnLongClickListener(longClickListener);
findViewById(R.id.b1).setOnDragListener(dragListener);
findViewById(R.id.b2).setOnDragListener(dragListener);
findViewById(R.id.b3).setOnDragListener(dragListener);
}
OnLongClickListener longClickListener = new OnLongClickListener() {
@Override
public boolean onLongClick(View view) {
DragShadow dragShadow = new DragShadow(view);
ClipData clipData = ClipData.newPlainText("","");
view.startDrag(clipData, dragShadow, view, 0);
return true;
}
};
private class DragShadow extends View.DragShadowBuilder{
ColorDrawable greyBox;
public DragShadow(View v){
super(v);
greyBox = new ColorDrawable(R.color.button_material_light);
}
@Override
public void onDrawShadow(Canvas canvas) {
greyBox.draw(canvas);
}
@Override
public void onProvideShadowMetrics(Point shadowSize, Point
shadowTouchPoint) {
View v = getView();
int height = (int) v.getHeight();
int width = (int) v.getWidth();
greyBox.setBounds(0,0,width,height);
shadowSize.set(width,height);
shadowTouchPoint.set((int) width/2,(int) height/2);
}
}
OnDragListener dragListener = new OnDragListener() {
@Override
public boolean onDrag(View view, DragEvent dragEvent) {
int dEvent = dragEvent.getAction();
switch (dEvent) {
case DragEvent.ACTION_DRAG_ENTERED:
Log.i("Drag Event", "Entered");
break;
case DragEvent.ACTION_DRAG_EXITED:
Log.i("Drag Event", "Exited");
break;
case DragEvent.ACTION_DROP:
Button b = (Button) view;
if (b.getText().toString().matches("")) {
Button dragged = (Button) dragEvent.getLocalState();
CharSequence a = b.getText();
b.setText(dragged.getText());
dragged.setText(a);
} else{
Toast.makeText(getApplicationContext(),"inserting button should be empty",Toast.LENGTH_SHORT).show();
}
break;
}
return true;
}
};
}
【问题讨论】：
标签： java android drag-and-drop drag onlongclicklistener