将值从MainActivity传递到扩展片段的Java_类失败
为了更好地理解将值从MainActivity传递到扩展片段的Java_类失败,java,android,android-fragments,fragment,Java,Android,Android Fragments,Fragment,为了更好地理解片段的工作原理,我创建了一个mainactivity,它的布局有一个。我创建了两个java类extendfragment,每个类都有自己的布局 在扩展fragment的java类中,我在的activitycreated()中初始化了我的视图textview,如下所示,在同一类的代码中,我创建了两个方法setbttnclicks(int clicks)和getbtnclicks()。从main活动中,我将按钮的点击次数指定给setbtnclicks(),并尝试通过调用onActivi
片段的工作原理,我创建了一个mainactivity
,它的布局有一个
。我创建了两个java类extendfragment
,每个类都有自己的布局
在扩展fragment
的java类中,我在的activitycreated()
中初始化了我的视图textview
,如下所示,在同一类的代码中,我创建了两个方法setbttnclicks(int clicks)
和getbtnclicks()
。从main活动
中,我将按钮的点击次数指定给setbtnclicks()
,并尝试通过调用onActivivtyCreated()
内部的getbtnclicks
来显示扩展fragment
的类的textview
上的点击次数。但问题是,此方法始终显示零,就好像单击次数没有增加一样
维护活动:
//global variable
private int i = 0;
...
...
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Fragment mSelectedFragment;
FragmentManager mFragmentManager;
FragmentTransaction mFragmentTransaction;
switch (v.getId()) {
case R.id.btn00:
mSelectedFragment = new Fragment00();
mFragmentManager = getFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.fragment00ID, mSelectedFragment);
mFragmentTransaction.commit();
mFragment00.setBtnClicks(i);
i++;
break;
Java_类“Fragment00”
片段事务之前的增量i
switch (v.getId()) {
case R.id.btn00:
i++;
mSelectedFragment = new Fragment00();
mFragmentManager = getFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.fragment00ID, mSelectedFragment);
mFragmentTransaction.commit();
mFragment00.setBtnClicks(i);
break;
一旦我实现了一个和你差不多的程序。目标是增加两个片段中的按钮点击次数。下面是代码。希望它能有所帮助:
MainActivity.java
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
public class MainActivity extends Activity implements OnClickListener{
Button btn1,btn2;
int click1=0,click2=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1=(Button)findViewById(R.id.btn1);
btn2=(Button)findViewById(R.id.btn2);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
}
@SuppressLint("NewApi")
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Fragment fragment = null;
if (v == btn1) {
// do stuff for button left
click1++;
Bundle bundle=new Bundle();
String clickstring1=Integer.toString(click1);
bundle.putString("name1",clickstring1 );
fragment = new FragButton1();
fragment.setArguments(bundle);
}
if (v == btn2) {
// do stuff for button right
click2++;
Bundle bundle=new Bundle();
String clickstring2=Integer.toString(click2);
bundle.putString("name2",clickstring2 );
fragment = new FragButton2();
fragment.setArguments(bundle);
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
}
else{
Log.e("MainActivity", "Error in creating fragment");
}
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton1 extends Fragment{
TextView tv;
public FragButton1(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton1, container, false);
String strtext=getArguments().getString("name1");
tv=(TextView)rootView.findViewById(R.id.tv_times1);
tv.setText(strtext);
return rootView;
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton2 extends Fragment{
TextView tv2;
public FragButton2(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton2, container, false);
tv2=(TextView)rootView.findViewById(R.id.tv_times2);
String strtext=getArguments().getString("name2");
tv2.setText(strtext);
return rootView;
}
}
FragButton1.java
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
public class MainActivity extends Activity implements OnClickListener{
Button btn1,btn2;
int click1=0,click2=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1=(Button)findViewById(R.id.btn1);
btn2=(Button)findViewById(R.id.btn2);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
}
@SuppressLint("NewApi")
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Fragment fragment = null;
if (v == btn1) {
// do stuff for button left
click1++;
Bundle bundle=new Bundle();
String clickstring1=Integer.toString(click1);
bundle.putString("name1",clickstring1 );
fragment = new FragButton1();
fragment.setArguments(bundle);
}
if (v == btn2) {
// do stuff for button right
click2++;
Bundle bundle=new Bundle();
String clickstring2=Integer.toString(click2);
bundle.putString("name2",clickstring2 );
fragment = new FragButton2();
fragment.setArguments(bundle);
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
}
else{
Log.e("MainActivity", "Error in creating fragment");
}
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton1 extends Fragment{
TextView tv;
public FragButton1(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton1, container, false);
String strtext=getArguments().getString("name1");
tv=(TextView)rootView.findViewById(R.id.tv_times1);
tv.setText(strtext);
return rootView;
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton2 extends Fragment{
TextView tv2;
public FragButton2(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton2, container, false);
tv2=(TextView)rootView.findViewById(R.id.tv_times2);
String strtext=getArguments().getString("name2");
tv2.setText(strtext);
return rootView;
}
}
FragButton2.java
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
public class MainActivity extends Activity implements OnClickListener{
Button btn1,btn2;
int click1=0,click2=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1=(Button)findViewById(R.id.btn1);
btn2=(Button)findViewById(R.id.btn2);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
}
@SuppressLint("NewApi")
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Fragment fragment = null;
if (v == btn1) {
// do stuff for button left
click1++;
Bundle bundle=new Bundle();
String clickstring1=Integer.toString(click1);
bundle.putString("name1",clickstring1 );
fragment = new FragButton1();
fragment.setArguments(bundle);
}
if (v == btn2) {
// do stuff for button right
click2++;
Bundle bundle=new Bundle();
String clickstring2=Integer.toString(click2);
bundle.putString("name2",clickstring2 );
fragment = new FragButton2();
fragment.setArguments(bundle);
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
}
else{
Log.e("MainActivity", "Error in creating fragment");
}
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton1 extends Fragment{
TextView tv;
public FragButton1(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton1, container, false);
String strtext=getArguments().getString("name1");
tv=(TextView)rootView.findViewById(R.id.tv_times1);
tv.setText(strtext);
return rootView;
}
}
import android.annotation.SuppressLint;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
@SuppressLint("NewApi")
public class FragButton2 extends Fragment{
TextView tv2;
public FragButton2(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragbutton2, container, false);
tv2=(TextView)rootView.findViewById(R.id.tv_times2);
String strtext=getArguments().getString("name2");
tv2.setText(strtext);
return rootView;
}
}
这里有两个按钮,点击一个按钮,将启动一个新的片段,片段将显示一个按钮在文本视图中被点击的次数。我这样做了,但我得到了同样的结果,我也考虑过使用bundle,但你知道为什么没有bundle它不能工作吗?请回答另一个问题,“Bundle savedInstanceState”参数的用途是什么?如果它不具有包含
标记的mainActivity的所有值,则传递到OnActivity Created的参数“Bundle savedInstanceState”参数的用途是什么?我始终使用Bundle将数据从活动传递到片段。我不知道为什么没有Bundle它不起作用。还有“Bundle savedInstanceState”保存活动的状态,即,假设您要将一些有关方向更改的数据从potrait传递到横向。然后您可以将要保存的内容放入savedInstanceState,然后您可以通过方法public void on RestoreInstanceState从savedInstanceState检索保存的数据(Bundle savedInstanceState)