Java 如何以编程方式更改 ActionBar 中的 MenuItem 图标
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How to change MenuItem icon in ActionBar programmatically
提问by veinhorn
How to change MenuItem icon in ActionBar programmatically? I tried to use
如何以编程方式更改 ActionBar 中的 MenuItem 图标？我试着用
MenuItem menuItem = (MenuItem)findViewById(R.id.action_settings);
menuItem.setIcon(getResources().getDrawable(R.drawable.ic_launcher))
but it doesn't work. This is my code:
但它不起作用。这是我的代码：
MainActivity
主要活动
package com.test;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
public class MainActivity extends ActionBarActivity {
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button)findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MenuItem menuItem = (MenuItem)findViewById(R.id.action_settings);
menuItem.setIcon(getResources().getDrawable(R.drawable.ic_launcher));
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
main.xml
主文件
<menu
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".MainActivity" >
<item
android:icon="@drawable/action_settings"
android:id="@+id/action_settings"
android:title="@string/action_settings"
android:orderInCategory="100"
app:showAsAction="always"/>
</menu>
activity_main
活动主
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent">
<Button
android:id="@+id/button"
android:text="Set icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
This is the exception that i've had after running:
这是我运行后的异常：
MenuItem menuItem = (MenuItem)findViewById(R.id.action_settings);
11-09 19:52:40.471 1735-1735/com.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.ClassCastException: android.support.v7.internal.view.menu.ActionMenuItemView
at com.test.MainActivity.onClick(MainActivity.java:19)
at android.view.View.performClick(View.java:2485)
at android.view.View$PerformClick.run(View.java:9080)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
采纳答案by Lalith Mohan
You can't use findViewById() on menu items in onCreate() because the menu layout isn't inflated yet. You could create a global Menu variable and initialize it in the onCreateOptionsMenu() and then use it in your onClick().
您不能在 onCreate() 中的菜单项上使用 findViewById()，因为菜单布局尚未膨胀。您可以创建一个全局菜单变量并在 onCreateOptionsMenu() 中对其进行初始化，然后在您的 onClick() 中使用它。
private Menu menu;
In your onCreateOptionsMenu()
在你的 onCreateOptionsMenu()
this.menu = menu;
In your button's onClick() method
在按钮的 onClick() 方法中
menu.getItem(0).setIcon(ContextCompat.getDrawable(this, R.drawable.ic_launcher));
回答by iamthevoid
I resolved this problem this way:
我这样解决了这个问题：
In onCreateOptionsMenu:
在onCreateOptionsMenu：
this.menu = menu;
this.menu.add("calendar");
ImageView imageView = new ImageView(getActivity());
imageView.setMinimumHeight(128);
imageView.setMinimumWidth(128);
imageView.setImageDrawable(yourDrawable);
MenuItem item = this.menu.getItem(0);
item.setActionView(imageView);
in onOptionsItemSelected:
在onOptionsItemSelected：
if (item.getOrder() == 0) {
//TODO
return true;
}
回答by marius
Lalith's answer is correct.
拉利斯的回答是正确的。
You may also try this approach:
你也可以试试这个方法：
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
invalidateOptionsMenu();
}
});
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
MenuItem settingsItem = menu.findItem(R.id.action_settings);
// set your desired icon here based on a flag if you like
settingsItem.setIcon(ContextCompat.getDrawable(this, R.drawable.ic_launcher));
return super.onPrepareOptionsMenu(menu);
}
回答by Alen Siljak
Instead of getViewById(), use
代替 getViewById()，使用
MenuItem item = getToolbar().getMenu().findItem(Menu.FIRST);
replacing the Menu.FIRSTwith your menu item id.
用Menu.FIRST您的菜单项 ID替换。
回答by Mohale
This works for me. It should be in your onOptionsItemSelected(MenuItem item)method item.setIcon(R.drawable.your_icon);
这对我有用。它应该在你的onOptionsItemSelected(MenuItem item)方法中 item.setIcon(R.drawable.your_icon);
回答by Keshav Gera
Its Working
它的工作
MenuItem tourchmeMenuItem; // Declare Global .......
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.search, menu);
menu.findItem(R.id.action_search).setVisible(false);
tourchmeMenuItem = menu.findItem(R.id.done);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
case R.id.done:
if(LoginPreferences.getActiveInstance(CustomViewFinderScannerActivity.this).getIsFlashLight()){
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
mScannerView.setFlash(false);
LoginPreferences.getActiveInstance(CustomViewFinderScannerActivity.this).setIsFlashLight(false);
tourchmeMenuItem.setIcon(getResources().getDrawable(R.mipmap.torch_white_32));
}
}else {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
mScannerView.setFlash(true);
LoginPreferences.getActiveInstance(CustomViewFinderScannerActivity.this).setIsFlashLight(true);
tourchmeMenuItem.setIcon(getResources().getDrawable(R.mipmap.torch_cross_white_32));
}
}
break;
}
回答by splhead
to use in onMenuItemClick(MenuItem item)just do invalidateOptionsMenu();
item.setIcon(ContextCompat.getDrawable(this, R.drawable.ic_baseline_play_circle_outline_24px));
用于onMenuItemClick(MenuItem item)只是做invalidateOptionsMenu();
item.setIcon(ContextCompat.getDrawable(this, R.drawable.ic_baseline_play_circle_outline_24px));
回答by korchix
Here is how i resolved this:
这是我解决这个问题的方法：
1 - create a Field Variable like: private Menu mMenuItem;
1 - 创建一个字段变量，如： private Menu mMenuItem;
2 - override the method invalidateOptionsMenu():
2 - 覆盖方法 invalidateOptionsMenu()：
@Override
public void invalidateOptionsMenu() {
super.invalidateOptionsMenu();
}
3 - call the method invalidateOptionsMenu()in your onCreate()
3 - 调用invalidateOptionsMenu()你的方法onCreate()
4 - add mMenuItem = menuin your onCreateOptionsMenu(Menu menu)like this:
4 -添加mMenuItem = menu在你onCreateOptionsMenu(Menu menu)这样的：
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.webview_menu, menu);
mMenuItem = menu;
return super.onCreateOptionsMenu(menu);
}
5 - in the method onOptionsItemSelected(MenuItem item)change the icon you want like this:
5 - 在该方法中onOptionsItemSelected(MenuItem item)更改您想要的图标，如下所示：
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.R.id.action_settings:
mMenuItem.getItem(0).setIcon(R.drawable.ic_launcher); // to change the fav icon
//Toast.makeText(this, " " + mMenuItem.getItem(0).getTitle(), Toast.LENGTH_SHORT).show(); <<--- this to check if the item in the index 0 is the one you are looking for
return true;
}
return super.onOptionsItemSelected(item);
}
