[英]How to set Visibility for a float Action menu from another Activity
我創建了一個浮動動作菜單,其中包含一個活動中的浮動動作按鈕,我需要在所有活動中顯示相同的屏幕,但沒有此浮動動作菜單,這是我試圖在主活動中設置的Visbily(VIEW.Invisible)新活動向我顯示了一個空對象引用錯誤,我該如何解決
這是mainActivity,其中包含浮動操作菜單
public class MenuActivity extends AppCompatActivity {
FloatingActionButton SplitCheck, HoldItem, VoidItem, ChangeNoOfCovers, Payment;
public static FloatingActionMenu mainFM;
@Override
protected void onCreate(Bundle savedInstanceState) {
mainFM = (FloatingActionMenu) findViewById(R.id.mainFAB);
SplitCheck = (FloatingActionButton) findViewById(R.id.splitCheck);
HoldItem = (FloatingActionButton) findViewById(R.id.holdItem);
VoidItem = (FloatingActionButton) findViewById(R.id.voidItem);
ChangeNoOfCovers = (FloatingActionButton) findViewById(R.id.changeNoCover);
Payment = (FloatingActionButton) findViewById(R.id.paymentID);
mainFM.setClosedOnTouchOutside(true);
...........................
.................
}
}
這是我的第二個活動
package abtech.waiteriano.com.waitrer;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import com.github.clans.fab.FloatingActionMenu;
public class TakeAwayActivity extends AppCompatActivity {
private FloatingActionButton fabNew;
private android.support.v7.widget.Toolbar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_take_away);
fabNew = (FloatingActionButton) findViewById(R.id.newOrderTa);
final FloatingActionMenu mainFM = (FloatingActionMenu) findViewById(R.id.mainFAB);
final boolean showButton = getIntent().getBooleanExtra("HIDE_FAB" , false);
mainFM.setVisibility(showButton ? View.VISIBLE : View.INVISIBLE);
// MenuActivity.mainFM.setVisibility(View.INVISIBLE);
fabNew.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final Intent i = new Intent(TakeAwayActivity.this, MenuActivity.class);
i.putExtra("HIDE_FAB", true);
startActivity(i);
}
});
}
}
您不能將靜態變量用於此類使用。
在您的特定情況下,您嘗試在執行onCreate之前訪問MenuActivity.mainFM
,因此必須為null。
好的方法是在startActivity Intent中添加一個附加項,然后在活動的onCreate方法中添加該附加項,然后顯示或不顯示按鈕。
final Intent intent = new Intent(TakeAwayActivity.this, MenuActivity.class);
intent.putExtra(MenuActivity.EXTRA_SHOW_BUTTON_KEY, true);
startActivity(intent);
然后在您的活動中:
public class MenuActivity extends AppCompatActivity {
public static final String EXTRA_SHOW_BUTTON_KEY = "EXTRA_SHOW_BUTTON_KEY";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_layout);
final FloatingActionMenu mainFM = (FloatingActionMenu) findViewById(R.id.mainFAB);
final boolean showButton = getIntent().getBooleanExtra(EXTRA_SHOW_BUTTON_KEY , false);
mainFM.setVisibility(showButton ? View.VISIBLE : View.INVISIBLE);
// ...
}
}
由於在您的MenuActivity
您必須始終隱藏FloatingActionButton
在MenuActivity
onCreate
嘗試以下MenuActivity
:
setContentView(R.layout.activity_take_away);
mainFM = (FloatingActionMenu) findViewById(R.id.mainFAB);
mainFM.setVisibility(View.INVISIBLE);
我認為不需要意圖,因為它必須始終隱藏
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