安卓:无法更改片段中按钮的背景(可绘制对象)

Question

我有以下问题无法解决：

我正在构建一个具有多个片段的安卓应用程序。在第二个片段上有一个按钮，每次按下按钮时都需要更改背景(即可绘制对象)。在我添加更多逻辑之前，我希望它起作用，但我无法让它工作。非常感谢帮助！

round_button_f2_decrease.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list
xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="oval">
<solid android:color="@color/colorButtonF1Decrease" />
</shape>
</item>
<item
android:drawable="@drawable/ic_trending_down_white_24px"
android:gravity="center" />
</layer-list>

round_button_f2_increase.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="oval">
<solid android:color="@color/colorButtonF1Increase" />
</shape>
</item>
<item
android:drawable="@drawable/ic_trending_up_white_24px"
android:gravity="center" />
</layer-list>

fragment_two.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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/f2_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="Placeholder"
android:textAlignment="center"
android:textSize="40sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/f2_button"
android:layout_width="56dp"
android:layout_height="56dp"
android:layout_marginBottom="24dp"
android:layout_marginEnd="24dp"
android:elevation="2dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
</android.support.constraint.ConstraintLayout>

片段二.java

import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;
public class FragmentTwo extends Fragment {
private static final String TAG = "FragmentTwo";
private Button mbtnSort;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_two, container, false);
mbtnSort = view.findViewById(R.id.f2_button);
mbtnSort.setBackground(getResources().getDrawable(R.drawable.round_button_f2_decrease));
mbtnSort.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Drawable btnBackground = mbtnSort.getBackground();
if (btnBackground.equals(getResources().getDrawable(R.drawable.round_button_f2_decrease))) {
Toast.makeText(getActivity(), "IF", Toast.LENGTH_LONG).show();
mbtnSort.setBackground(getResources().getDrawable(R.drawable.round_button_f2_increase));
} else {
Toast.makeText(getActivity(), "ELSE", Toast.LENGTH_LONG).show();
mbtnSort.setBackground(getResources().getDrawable(R.drawable.round_button_f2_decrease));
}
}
});
return view;
}
}

Answer 1

使用

mbtnSort.setBackground(R.drawable.round_button_f2_decrease);

Answer 2

现在它可以工作了：

public class FragmentThree extends Fragment {
private static final String TAG = "FragmentThree";
private Button mbtnSort;
private boolean mbtnPressed = false;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_three, container, false);
mbtnSort = view.findViewById(R.id.f3_button);
mbtnSort.setBackgroundResource(R.drawable.round_button_f2_decrease);
mbtnSort.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mbtnPressed == true) {
Toast.makeText(getActivity(), "IF", Toast.LENGTH_LONG).show();
mbtnSort.setBackgroundResource(R.drawable.round_button_f2_decrease);
mbtnPressed = false;
} else {
Toast.makeText(getActivity(), "ELSE", Toast.LENGTH_LONG).show();
mbtnSort.setBackgroundResource(R.drawable.round_button_f2_increase);
mbtnPressed = true;
}
}
});
return view;
}
}

Answer 3

我想我理解你试图做什么你的问题不在更改背景中 您对背景本身的问题

我搜索你很多东西，知道如何回到地面并与你的round_button_f2_decrease.xml一起检查

所以太难了

如果您使用标志或某些东西来做到这一点，它现在对您的问题会有所帮助

我发现这可能会有所帮助 比较安卓中的两个可绘制对象

而这个 比较两个可绘制对象中的资源