[英]Android: Unable to change background (drawable) of a button in Fragment
我有以下无法解决的问题:
我正在构建具有多个片段的android应用。 在第二个片段上,有一个按钮,每次按下该按钮时,都需要更改背景(即可绘制对象)。 在我添加更多逻辑之前,我希望它能够正常工作,但是我无法使其正常工作。 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>
FragmentTwo.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;
}
}
采用
mbtnSort.setBackground(R.drawable.round_button_f2_decrease);
现在可以正常工作:
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;
}
}
我想我了解您要如何在不改变背景的情况下解决您的问题?
我在搜寻您很多东西,以了解如何扎根,并使用round_button_f2_decrease.xml进行检查
所以很难
如果您用旗帜或其他东西来做,这将对您现在的问题有所帮助
我发现这可能有助于比较android中的两个drawable
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