我在做一個登記畫面在我的應用程序中的第一頁,在MainActivity.java我把:登記屏幕的Android
public class MainActivity extends Activity {
private EditText username=null;
private EditText password=null;
private TextView attempts;
private Button login;
int counter = 3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
username = (EditText)findViewById(R.id.editText1);
password = (EditText)findViewById(R.id.editText2);
attempts = (TextView)findViewById(R.id.textView3);
attempts.setText(Integer.toString(counter));
login = (Button)findViewById(R.id.button1);
}
public void login(View view){
if(username.getText().toString().equals("admin") &&
password.getText().toString().equals("admin")){
Toast.makeText(getApplicationContext(), "Redirecting...",
Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(getApplicationContext(), "Wrong Credentials",
Toast.LENGTH_SHORT).show();
attempts.setBackgroundColor(Color.RED);
counter--;
attempts.setText(Integer.toString(counter));
if(counter==0){
login.setEnabled(false);
}
}}
@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;
}
}
在XML頁面我把:
<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="92dp"
android:text="username"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="36dp"
android:text="password"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView1"
android:layout_alignBottom="@+id/textView1"
android:layout_marginLeft="30dp"
android:layout_toRightOf="@+id/textView1"
android:ems="10" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/editText1"
android:ems="10"
android:inputType="textPassword" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/editText2"
android:layout_centerHorizontal="true"
android:layout_marginTop="72dp"
android:text="attempts" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@+id/textView3"
android:layout_below="@+id/textView3"
android:layout_marginTop="42dp"
android:text="login" />
</RelativeLayout>
寫作時,我得到的錯誤是在Java代碼:
username = (EditText)findViewById(R.id.editText1);
editText1不能得到解決或不一個領域。 相同editText2,textView3和button1
請任何幫助嗎?
導入正確的R文件 – CQM
我做了導入,如何導入正確的R文件? – Angel
我的代碼沒有收到任何錯誤。但是你沒有爲你的button1調用onClick()方法。嘗試清理和建立項目。 –