我遇到了这个问题,与FC有关。
当应用程序启动时,如何将此TextView(msg)的可见性设置为false?
private TextView msg, NameOut, DateOut;
msg = (TextView) findViewById(R.id.txtviewOut) ;
问题出在这里...(down the line)
msg.setVisibility(View.INVISIBLE);//set visibility to false on create
当应用程序启动时,如何将此TextView(msg)的可见性设置为false?
在#1回答编辑之后更新
好的,这是所有的代码:
fragment_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment">
<EditText
android:id="@+id/textenter"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:layout_below="@+id/lbledt1"
android:layout_alignParentLeft="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Enter Name"
android:id="@+id/lbledt1"
android:layout_marginTop="26dp"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Enter your date of birth (e.g. xx July 19xx)"
android:id="@+id/textView"
android:layout_below="@+id/textenter"
android:layout_centerHorizontal="true"
android:layout_marginTop="57dp" />
<EditText
android:id="@+id/editText"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:layout_below="@+id/textView"
android:layout_alignParentLeft="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Press this button"
android:id="@+id/button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="You have been awesome since"
android:id="@+id/txtviewOut"
android:layout_marginTop="86dp"
android:textIsSelectable="false"
android:layout_below="@+id/button"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:id="@+id/txtoutName"
android:textIsSelectable="false"
android:layout_alignBottom="@+id/txtviewOut"
android:layout_centerHorizontal="true"
android:layout_marginBottom="41dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:id="@+id/txtOutDate"
android:layout_marginTop="28dp"
android:textIsSelectable="false"
android:layout_below="@+id/txtviewOut"
android:layout_centerHorizontal="true" />
MainActivity.java:
package com.example.helloandroidstudio;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
private Button btnClick;
private EditText Name, Date;
private TextView msg, NameOut, DateOut;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnClick = (Button) findViewById(R.id.button) ;
Name = (EditText) findViewById(R.id.textenter) ;
Date = (EditText) findViewById(R.id.editText) ;
msg = (TextView) findViewById(R.id.txtviewOut) ;
NameOut = (TextView) findViewById(R.id.txtoutName) ;
DateOut = (TextView) findViewById(R.id.txtOutDate) ;
// msg.setVisibility(View.GONE);//set visibility to false on create
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
public void onClick(View v)
{
if (v == btnClick)
{
if (Name.equals("") == false && Date.equals("") == false)
{
NameOut = Name;
DateOut = Date;
msg.setVisibility(View.VISIBLE);
}
else
{
msg.setText("Please complete both fields");
msg.setVisibility(View.VISIBLE);
}
}
}
@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.
switch (item.getItemId()) {
case R.id.action_settings:
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
我试过使用setInvisibility(View.GONE),但仍然出现了FC。
我检查了id值,有一个aid值被分配并且我确实对对象进行了类型转换...
请记住,我以前做过C#,但这是我第一个Java/Android应用程序,请谅解我。