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我在android studio中創建了一個導航抽屜活動。現在，我想修改代碼，以便通過onClick屬性更改菜單項的可見性。如何通過Android Studio中的複選框控制menuItems的可見性
主要的應用程序包括幾個不同的複選框，當用戶點擊其中任何一個，我希望應用程序顯示在菜單中的特定項目，然後將剩下不可見。
我宣佈幾個整數並初始化它們爲0。每當，用戶選擇一個複選框，爲此我要顯示的特定項目的整數值遞增。
然後，在最後，如果有整的價值仍然等於零，菜單項將被設置爲不可見否則這將是可見的。
onCheckBoxSelected（）方法用於此。當用戶選擇任何一個複選框時，整數值會遞增。
這裏是我的MainActivity.java
package com.example.android.smartswitch;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
int scheduleSettings = 0;
int randomDelay = 0;
int temperatureSettings = 0;
int humiditySettings = 0;
int manualControl = 0;
int logging = 0;
int generalSettings = 0;
public void onCheckBoxSelected (View view) {
boolean checked = ((CheckBox)view).isChecked();
switch (view.getId()) {
//Using multiple switch statements to decide the visibility status of the item in the navigation drawer.
case R.id.illuminatorBox1:
if (checked) {
scheduleSettings++;
randomDelay++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.heaterBox2:
if (checked) {
temperatureSettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.timeHeaterBox3:
if (checked) {
scheduleSettings++;
temperatureSettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.airConditionBox4:
if (checked) {
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.timeAirConditionBox5:
if (checked) {
scheduleSettings++;
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.humidifierBox6:
if (checked) {
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.timeHumidifierBox7:
if (checked) {
scheduleSettings++;
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.airDryerBox8:
if (checked) {
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
case R.id.timeAirDryerBox9:
if (checked) {
scheduleSettings++;
humiditySettings++;
manualControl++;
logging++;
generalSettings++;
}
break;
default:
Toast.makeText(this, "Default Case Applied.... Find the *BUG*", Toast.LENGTH_LONG);
break;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
toolbar.isShown();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
Menu nav_menu = navigationView.getMenu(); //To hide items from the menu if conditions aren't fulfilled.
if (scheduleSettings == 0)
nav_menu.findItem(R.id.scheduleSettingsSideBar).setVisible(true);
else if (randomDelay == 0)
nav_menu.findItem(R.id.randomDelaySideBar).setVisible(false);
else if (temperatureSettings == 0)
nav_menu.findItem(R.id.tempSettingsSideBar).setVisible(false);
else if (humiditySettings == 0)
nav_menu.findItem(R.id.humiditySettingsSideBar).setVisible(false);
else if (manualControl == 0)
nav_menu.findItem(R.id.manualSettingsSideBar).setVisible(false);
else if (logging == 0)
nav_menu.findItem(R.id.loggingSideBar).setVisible(false);
else if (generalSettings == 0)
nav_menu.findItem(R.id.generalSettingsSideBar).setVisible(false);
}
int controllerButton = 1; //Depending on this value, the main screen text will change.
public void onButtonClick(View view) {
switch (view.getId()) {
case R.id.settingsButton:
Intent intent = new Intent(this, logging_screen.class);
startActivity(intent);
break;
case R.id.controllerButton:
if (controllerButton == 1) {
Button button1 = (Button) findViewById(R.id.controllerButton);
button1.setBackgroundColor(Color.GREEN); //Changing the background of the controllerButton.
button1.setText(getString(R.string.controller_off_text));
Button headerButton = (Button) findViewById(R.id.headerText);
headerButton.setBackgroundColor(Color.RED);
headerButton.setTextColor(Color.BLACK);
headerButton.setText(getString(R.string.banner_off_text));
controllerButton = 0; //Setting the button int to zero for next change.
} else if (controllerButton == 0) {
Button button1 = (Button) findViewById(R.id.controllerButton);
button1.setBackgroundColor(Color.parseColor("#33b5e5")); //Changing the background of the controllerButton.
button1.setText(getString(R.string.controller_on_text));
Button headerButton = (Button) findViewById(R.id.headerText);
headerButton.setBackgroundColor(Color.parseColor("#000000"));
headerButton.setTextColor(Color.WHITE);
headerButton.setText(getString(R.string.banner_on_text));
controllerButton = 1; //Setting the button int to one for next change. An altering loop.
}
break;
}
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@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) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.scheduleSettingsSideBar) {
//Intent to send the user to scheduleSettings Screen.
Intent intent = new Intent(this, schedule_settings.class);
startActivity(intent);
} else if (id == R.id.manualSettingsSideBar) {
Intent intent = new Intent(this, manual_control.class);
startActivity(intent);
} else if (id == R.id.tempSettingsSideBar) {
//Intent to send the user to tempSettings Screen.
Intent intent = new Intent(this, temp_screen.class);
startActivity(intent);
} else if (id == R.id.randomDelaySideBar) {
Intent intent = new Intent(this, random_delay.class);
startActivity(intent);
} else if (id == R.id.humiditySettingsSideBar) {
Intent intent = new Intent(this, humidity_settings.class);
startActivity(intent);
} else if (id == R.id.loggingSideBar) {
//Intent to send the user to loggingSidebar.
Intent intent = new Intent(this, logging_screen.class);
startActivity(intent);
} else if (id == R.id.generalSettingsSideBar) {
Intent intent = new Intent(this, general_settings.class);
startActivity(intent);
} else if (id == R.id.playSliderAgain) {
//We normally won't show the welcome slider again in real app
// but this is for testing
slidingScreenLauncher prefManager = new slidingScreenLauncher(getApplicationContext());
// make first time launch TRUE
prefManager.setFirstTimeLaunch(true);
startActivity(new Intent(MainActivity.this, WelcomeActivity.class));
finish();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
源代碼，但，這個程序有一個錯誤，被默認顯示的菜單項，我不知道爲什麼。該應用程序正常運行，除了這個之外，其他事情都按預期完成
請幫助，因爲如果此問題依然存在，我將無法改進我的應用。這將具有相同的輸出（設置菜單項不可見的）任何其他辦法，也歡迎.....
我嘗試過，但什麼菜nav_menu = navigationView.getMenu（）;'沒有在任何地方，除了工作onCreate方法....並且我不能在外部使用nav_menu onCreate（）..... –
嘗試創建nav_menu作爲全局變量。外部onCreate類型'菜單nav_menu;'然後內部onCreate'nav_menu = navigationView.getMenu（）;'如果你這樣做，你可以訪問nav_menu內onCheckBoxSelected（）; – niju
感謝您的幫助！問題解決了..... –