blocks|key|1028067|text|重写onBackPressed方法，如果要处理设备上的后退按钮，则不执行任何操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1028068|@Override
public+void+onBackPressed()+{
+++if+(shouldAllowBack())+{
+++++++super.onBackPressed();
+++}+else+{
+++++++doSomething();
+++}
}|code-block|syntax|javascript|1028069|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Override the onBackPressed method and do nothing if you meant to handle the back button on the device.

<pre><code>@Override
public void onBackPressed() {
 if (shouldAllowBack()) {
 super.onBackPressed();
 } else {
 doSomething();
 }
}
</code></pre>

blocks|key|1028006|text|如果正在寻找更高的api级别2.0或更高版本，这将非常有效|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1028007|@Override
public+void+onBackPressed()+{
++++//+Do+Here+what+ever+you+want+do+on+back+press;
}|code-block|syntax|javascript|1028008|如果希望android+api级别达到1.6。|1028009|@Override
public+boolean+onKeyDown(int+keyCode,+KeyEvent+event)+{
+++++if+(keyCode+==+KeyEvent.KEYCODE_BACK)+{
+++++//preventing+default+implementation+previous+to+android.os.Build.VERSION_CODES.ECLAIR
+++++return+true;
+++++}
+++++return+super.onKeyDown(keyCode,+event);++++
}|1028010|在你的活动中编写上面的代码，以防止按下后退按钮|1028011|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

If looking for a higher api level 2.0 and above
this will work great

<pre><code>@Override
public void onBackPressed() {
 // Do Here what ever you want do on back press;
}
</code></pre>

If looking for android api level upto 1.6.

<pre><code>@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
 if (keyCode == KeyEvent.KEYCODE_BACK) {
 //preventing default implementation previous to android.os.Build.VERSION_CODES.ECLAIR
 return true;
 }
 return super.onKeyDown(keyCode, event); 
}
</code></pre>

Write above code in your Activity to prevent back button pressed

blocks|key|813412|text|我正在使用它.............|type|unstyled|depth|inlineStyleRanges|entityRanges|data|813413|+@Override
public+boolean+onKeyDown(int+keyCode,+KeyEvent+event)+{
++++if(keyCode==KeyEvent.KEYCODE_BACK)
++++++++Toast.makeText(getApplicationContext(),+"back+press",++++++
+++++Toast.LENGTH_LONG).show();

++++return+false;
+++++++//+Disable+back+button..............
}|code-block|syntax|javascript|813414|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I am using it.............

<pre><code> @Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
 if(keyCode==KeyEvent.KEYCODE_BACK)
 Toast.makeText(getApplicationContext(), "back press", 
 Toast.LENGTH_LONG).show();

 return false;
 // Disable back button..............
}
</code></pre>

blocks|key|813637|text|只需覆盖onBackPressed()方法，不需要调用onBackPressed方法的超类或其他方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|813638|@Override
public+void+onBackPressed()
{

}|code-block|syntax|javascript|813639|或者将当前活动传递给onBackPressed()方法。|813640|@Override
public+void+onBackPressed()
{
+++startActivity(new+Intent(this,+myActivity.class));++
+++finish();
}|813641|将您所需的活动名称替换为myActivity。|813642|如果您使用的是片段，那么首先调用callParentMethod()方法|813643|public+void+callParentMethod(){
++++context.onBackPressed();+//+instead+of+context+use+getActivity+or+something+related
}|813644|然后调用empty方法|813645|@Override
public+void+onBackPressed()
{

}|813646|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|10|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

Just override the onBackPressed() method and no need to call the super class of onBackPressed method or others..

<pre><code>@Override
public void onBackPressed()
{

}
</code></pre>

Or pass your current activity into the onBackPressed() method.

<pre><code>@Override
public void onBackPressed()
{
 startActivity(new Intent(this, myActivity.class)); 
 finish();
}
</code></pre>

Replace your require activity name to myActivity.

if you are using fragment then first of all call the callParentMethod() method

<pre><code>public void callParentMethod(){
 context.onBackPressed(); // instead of context use getActivity or something related
}
</code></pre>

then call the empty method

<pre><code>@Override
public void onBackPressed()
{

}
</code></pre>

blocks|key|1028146|text|如果你想要确保你的android客户端应用程序在你的活动被终止之前已经从某个服务器上注销了-->在它自己的线程上注销一个服务(这就是你应该做的)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1028147|禁用后退按钮不会为您解决任何问题。例如，当用户接到电话时，您仍然会遇到同样的问题。当接到电话时，你的活动在从网络得到可靠的回复之前，有大约同样多的机会被杀死。|1028148|这就是为什么你应该让一个服务在它自己的线程上等待来自网络的应答，如果没有成功，就让它重试。安卓服务不仅不太可能在得到回复之前被杀死，而且如果它在完成工作之前真的被杀死了，它总是可以被AlarmManager复活以再次尝试。|1028149|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

If you want to make sure your android client application is logged out from some server before your Activity gets killed --> log out with a service on its own thread (that's what you're supposed to do anyway).

Disabling the back button won't solve anything for you. You'll still have the same problem when the user receives a phone call for instance. When a phone call is received, your activity has about as much chances of getting killed before it gets a reliable answer back from the network. 

That's why you should let a service wait on its own thread for the answer from the network, and then make it try again if it doesn't succeed. The android service is not only much less likely to get killed before it gets an answer back, but should it really get killed before finishing the job, it can always get revived by AlarmManager to try again.

blocks|key|813572|text|您可以覆盖活动中的onBackPressed()方法，并删除对超类的调用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|813573|@Override
public+void+onBackPressed()+{
++//remove+call+to+the+super+class
++//super.onBackPressed();
}|code-block|syntax|javascript|813574|entityMap^0|9|F|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You can override the <code>onBackPressed()</code> method in your activity and remove the call to super class.

<pre><code>@Override
public void onBackPressed() {
 //remove call to the super class
 //super.onBackPressed();
}
</code></pre>

blocks|key|813451|text|如果您使用的是FragmentActivity。然后像这样做|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|813452|首先在你的Fragment中调用它。|813453|public+void+callParentMethod(){
++++getActivity().onBackPressed();
}|code-block|syntax|javascript|813454|然后在父FragmentActivity类中调用onBackPressed方法。|813455|@Override
public+void+onBackPressed()+{
++//super.onBackPressed();
++//create+a+dialog+to+ask+yes+no+question+whether+or+not+the+user+wants+to+exit
++...
}|813456|entityMap^0|7|G|0|5|8|0|0|4|G|O|D|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|R|$]]

if you are using <code>FragmentActivity</code>. then do like this

first call This inside your <code>Fragment</code>.

<pre><code>public void callParentMethod(){
 getActivity().onBackPressed();
}
</code></pre>

and then Call <code>onBackPressed</code> method in side your parent <code>FragmentActivity</code> class.

<pre><code>@Override
public void onBackPressed() {
 //super.onBackPressed();
 //create a dialog to ask yes no question whether or not the user wants to exit
 ...
}
</code></pre>

blocks|key|813545|text|只需使用以下代码:如果您希望禁用反向按压，则不要使用super.OnBackPressed()；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|813546|@Override
public+void+onBackPressed()+{

}|code-block|syntax|javascript|813547|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just using this code: If you want backpressed disable, you dont use super.OnBackPressed();

<pre><code>@Override
public void onBackPressed() {

}
</code></pre>

blocks|key|1028477|text|在android中禁用back按钮|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1028478|@Override
public+void+onBackPressed()+{
++++return;
}|code-block|syntax|javascript|1028479|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Disable back buttton in android

<pre><code>@Override
public void onBackPressed() {
 return;
}
</code></pre>

blocks|key|813352|text|如果你想在注销时禁用你的应用程序，你可以弹出一个不可取消的对话框。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|813353|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you want to disable your app while logging out, you can pop up a non-cancellable dialog.

blocks|key|1028316|text|你只需要重写back按钮的方法。如果您愿意，您可以将该方法保留为空，这样当您按下back按钮时不会发生任何事情。请看下面的代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1028317|@Override
public+void+onBackPressed()+
{
+++//+Your+Code+Here.+Leave+empty+if+you+want+nothing+to+happen+on+back+press.
}|code-block|syntax|javascript|1028318|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You just need to override the method for back button. You can leave the method empty if you want so that nothing will happen when you press back button. Please have a look at the code below:

<pre><code>@Override
public void onBackPressed() 
{
 // Your Code Here. Leave empty if you want nothing to happen on back press.
}
</code></pre>

blocks|key|1028466|text|从public+void+onBackPressed()+work+great中删除super.onBackPressed()。它在android+9上进行了测试|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1028467|entityMap^0|1|R|16|L|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

remove <code>super.onBackPressed()</code> from <code>public void onBackPressed()</code> work great.
its tested in android 9

blocks|key|1028346|text|对我来说，仅仅覆盖onBackPressed()并不起作用，但明确指出它应该启动哪个活动很有效：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1028347|@Override
public+void+onBackPressed(){
++Intent+intent+=+new+Intent(this,+ActivityYouWanToGoBack.class);
++startActivity(intent);
}|code-block|syntax|javascript|1028348|entityMap^0|9|F|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

For me just overriding <code>onBackPressed()</code> did not work but explicit pointing which activity it should start worked well:

<pre><code>@Override
public void onBackPressed(){
 Intent intent = new Intent(this, ActivityYouWanToGoBack.class);
 startActivity(intent);
}
</code></pre>

blocks|key|813648|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|813649|@Override
public+boolean+onKeyDown(int+keyCode,+KeyEvent+event)+{
+if+(keyCode+==+KeyEvent.KEYCODE_BACK)+{

+++return+true;
+}
+++return+super.onKeyDown(keyCode,+event);++++
}|code-block|syntax|javascript|813650|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this:

<pre><code>@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
 if (keyCode == KeyEvent.KEYCODE_BACK) {

 return true;
 }
 return super.onKeyDown(keyCode, event); 
}
</code></pre>

问在android中禁用后退按钮
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回答 14

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问在android中禁用后退按钮EN

回答 14

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问在android中禁用后退按钮
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