如何在图像安卓中添加拖放功能?

Question

我在主XML中有三个按钮，其中包含添加表格和椅子重置。当我单击添加表格时，它将在第二个布局中添加一个表格，与添加椅子相同。我想在添加第二个布局后移动两个图像，就像拖放一样。

主活动包含三个按钮。每次单击按钮时，它将传递到第二.java通过意图

MainActivity.Java

public class MainActivity extends AppCompatActivity {

private ArrayList<String> mSelecetdItems = new ArrayList<>();
public static final String SELECETD_ITEMS = "SELECETD_ITEMS";

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public  void addtable(View v){
this.mSelecetdItems.add("table");
showSecondActivity();
}
public  void addchair(View v){
this.mSelecetdItems.add("chair");
showSecondActivity();
}

private void showSecondActivity()
{
Intent i = new Intent(this,Second.class);
i.putStringArrayListExtra(SELECETD_ITEMS,this.mSelecetdItems);
startActivity(i);
}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putStringArrayList(SELECETD_ITEMS , mSelecetdItems);
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
this.mSelecetdItems = savedInstanceState.getStringArrayList(SELECETD_ITEMS);
}

activity_main.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="com.andiroot.restaurantbook.MainActivity">


<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:minHeight="?attr/actionBarSize"
android:background="#ff1e8622"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
</android.support.v7.widget.Toolbar>
<RelativeLayout
android:layout_width="368dp"
android:layout_height="495dp"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="64dp">
<Button
android:id="@+id/btn_addtbl"
style="@style/Widget.AppCompat.Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="76dp"
android:text="Add Table"
android:onClick="addtable"/>
<Button
android:id="@+id/btn_addchairs"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addchair"
android:layout_marginTop="27dp"
android:text="Add Chair"
android:layout_below="@+id/btn_addtbl"
android:layout_alignEnd="@+id/btn_addtbl" />
<Button
android:id="@+id/btn_reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignEnd="@+id/btn_addchairs"
android:layout_below="@+id/btn_addchairs"
android:layout_marginTop="51dp"
android:text="Reset" />
</RelativeLayout>

</android.support.constraint.ConstraintLayout>

Second.java

public class Second extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Toolbar toolbar = (Toolbar) findViewById(R.id.second_toolbar);
setSupportActionBar(toolbar);
ActionBar ab = getSupportActionBar();
ab.setDisplayHomeAsUpEnabled(true);
/*toolbar.setNavigationIcon((R.drawable.back_arrow));
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onBackPressed();
}
});*/

LinearLayoutCompat hall = (LinearLayoutCompat) findViewById(R.id.hall_layout);
Intent i = getIntent();

ArrayList<String> selecetdItems = i.getStringArrayListExtra(MainActivity.SELECETD_ITEMS);
for (String selecetdItem : selecetdItems) {
if (selecetdItem.equals("table")) {
addImageView(R.drawable.table, hall);
} else if (selecetdItem.equals("chair")) {
addImageView2(R.drawable.chair2, hall);
}
}

}
private void addImageView(int imageRes, LinearLayoutCompat hall) {
ImageView iv = new ImageView(this);
iv.setImageResource(imageRes);
iv.setLayoutParams(new android.view.ViewGroup.LayoutParams(250, 250));
iv.setMaxHeight(180);
iv.setMaxWidth(120);
iv.setPadding(15,15,0,0);
hall.addView(iv);
}
private void addImageView2(int imageRes, LinearLayoutCompat hall) {
ImageView iv2 = new ImageView(this);
iv2.setImageResource(imageRes);
iv2.setLayoutParams(new android.view.ViewGroup.LayoutParams(150, 150));
iv2.setMaxHeight(30);
iv2.setMaxWidth(30);
iv2.setPadding(25,0,0,0);
hall.addView(iv2);
}
activity_second.java

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/hall_layout"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.andiroot.restaurantbook.Second">
<android.support.v7.widget.Toolbar
android:id="@+id/second_toolbar"
android:minHeight="?attr/actionBarSize"
android:background="#ff1e8622"
android:layout_width="match_parent"
android:layout_height="wrap_content">

</android.support.v7.widget.Toolbar>
<!--
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/hall_layout2">
</RelativeLayout>
-->
</android.support.v7.widget.LinearLayoutCompat>

Answer 1

您需要在这些图像上实现 onTouchListener。

@Override
public boolean onTouch(View v, MotionEvent event) {
int width=cropperLayout.getLayoutParams().width;;
int height=cropperLayout.getLayoutParams().height;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
dX = v.getX() - event.getRawX();
dY = v.getY() - event.getRawY();
return true;
case MotionEvent.ACTION_MOVE:
if (width == windowWidth && height == windowHeight){}
else {
v.animate()
.x(event.getRawX() + dX)
.y(event.getRawY() + dY)
.setDuration(0)
.start();
if (event.getRawX() + dX + width > windowWidth) {
v.animate()
.x(windowWidth - width)
.setDuration(0)
.start();
}
if (event.getRawX() + dX < 0) {
v.animate()
.x(0)
.setDuration(0)
.start();
}
if (event.getRawY() + dY + height > windowHeight) {
v.animate()
.y(windowHeight - height)
.setDuration(0)
.start();
}
if (event.getRawY() + dY < 0) {
v.animate()
.y(0)
.setDuration(0)
.start();
}
return true;
}    
}
}