java 一起使用 Fragment 和 AppCompatActivity 类
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Using Fragment and AppCompatActivity classes together
提问by Ollie Atkins
Hi I'm trying to make an app which uses two different classes I'm aware I can't use extend with two classes in Java. How would I go about separating the below code into two different classes so one can extend Fragment and the other AppCompatActivity?
嗨，我正在尝试制作一个使用两个不同类的应用程序，我知道我不能使用 Java 中的两个类来扩展。我将如何将下面的代码分成两个不同的类，以便一个可以扩展 Fragment 和另一个 AppCompatActivity？
package com.example.oliver.myapplication;
import android.support.v4.app.Fragment;
import android.app.AlertDialog;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
import java.util.Random;
public class MyFragment extends AppCompatActivity, Fragment {
Button b, b2;
MediaPlayer nice, burp;
ImageButton img;
int n;
MediaPlayer [] s = new MediaPlayer[6];
AlertDialog.Builder adb;
public static MyFragment newInstance() {
MyFragment fragment = new MyFragment();
return fragment;
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.my_fragment, container, false);
img = (ImageButton) rootView.findViewById(R.id.img);
s[0] = MediaPlayer.create(MyFragment.this, R.raw.burp);
s[1] = MediaPlayer.create(MyFragment.this, R.raw.robert);
s[2] = MediaPlayer.create(MyFragment.this, R.raw.burp2);
img.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
for (int i = 0; i < 1; i++) {
Random r = new Random();
n = r.nextInt(3);
s[n].start();
}
}
});return rootView;
}}
回答by Karthiksrndrn
The above code is not valid Java.
上面的代码不是有效的 Java。
A class can only extend one class. You activity/fragment is extending 2 classes at the same time.
一个类只能扩展一个类。您的活动/片段同时扩展了 2 个类。
The class given above is a valid Fragment subclass, except for these lines :
上面给出的类是一个有效的 Fragment 子类，除了以下几行：
s[0] = MediaPlayer.create(MyFragment.this, R.raw.burp);
s[1] = MediaPlayer.create(MyFragment.this, R.raw.robert);
s[2] = MediaPlayer.create(MyFragment.this, R.raw.burp2);
Replace "MyFragment.this" with "MyFragment.getActivity()".
将“MyFragment.this”替换为“MyFragment.getActivity()”。
Now you can replace "extends AppCompatActivity, Fragment" with "extends Fragment"
现在您可以将“extends AppCompatActivity, Fragment”替换为“extends Fragment”
Now you have a valid Fragment.
现在你有了一个有效的 Fragment。
Create the AppCompatActivity yourself. Look up how you can add a fragment to an activity.
自己创建 AppCompatActivity。查看如何将片段添加到活动中。
As a tip in good programming practice, I suggested that you move the following code in onCreateView() to onActivityCreated() :
作为良好编程实践的提示，我建议您将 onCreateView() 中的以下代码移动到 onActivityCreated() ：
img = (ImageButton) rootView.findViewById(R.id.img);
s[0] = MediaPlayer.create(MyFragment.this, R.raw.burp);
s[1] = MediaPlayer.create(MyFragment.this, R.raw.robert);
s[2] = MediaPlayer.create(MyFragment.this, R.raw.burp2);
img.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
for (int i = 0; i < 1; i++) {
Random r = new Random();
n = r.nextInt(3);
s[n].start();
}
}
});
Change
改变
img = (ImageButton) rootView.findViewById(R.id.img);
to
到
img = (ImageButton) getView().findViewById(R.id.img);
