当我按下手机的“后退”按钮时，它会显示一个空白页面。当我再次按下“后退”按钮时，它会显示应用程序的主页。我想在第一次返回时进入 mainActivity 页面。
mainActivity代码:
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.text.style.SuperscriptSpan;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.os.Build;
public class MainActivity extends ActionBarActivity {
Button b1,b2,b3,b4,b5,b6,b7;
EditText e1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1=(Button)findViewById(R.id.call1);
e1=(EditText)findViewById(R.id.call);
b1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String no=e1.getText().toString();
Intent call=new Intent(Intent.ACTION_CALL);
call.setData(Uri.parse("tel:"+no));
startActivity(call);
}
});
b2=(Button)findViewById(R.id.sens_sms);
b2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent sendsms=new
Intent(getApplicationContext(),waytosms.class);
startActivity(sendsms);
}
});
b3=(Button)findViewById(R.id.facebook);
b3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent facebook=new Intent(MainActivity.this,facebook.class);
startActivity(facebook);
finish();
}
});
b4=(Button)findViewById(R.id.gmail);
b4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent facebook=new Intent(MainActivity.this,gmail.class);
startActivity(facebook);
}
});
b5=(Button)findViewById(R.id.utube);
b5.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent facebook=new Intent(MainActivity.this,utube.class);
startActivity(facebook);
}
});
b6=(Button)findViewById(R.id.google);
b6.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent facebook=new Intent(MainActivity.this,google.class);
startActivity(facebook);
}
});
b7=(Button)findViewById(R.id.twitter);
b7.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent facebook=new Intent(MainActivity.this,twitter.class);
startActivity(facebook);
}
});
}
}
这是我在这里使用 webview 打开 Facebook 页面的 Facebook 类:
public class facebook extends Activity{
WebView facebook;
@SuppressLint("SetJavaScriptEnabled")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.facebook);
facebook=(WebView)findViewById(R.id.webfacebook);
facebook.getSettings().setJavaScriptEnabled(true);
facebook.loadUrl("https://facebook.com");
}
我在这里实现了 onbackPressed() 并调用了 finished() onbackpressed 方法对此完全没有影响。
@SuppressLint("NewApi")
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
finish();
Intent i=new Intent(facebook.this,MainActivity.class);
startActivity(i);
}
}
1> first is main activity page where there are icon of social sites when i click on facebook icon it will open facebook as 2nd facebookActivity page,3> when i clicked back it will open a blank page and4>. nd when i again press back button it will opened the main activity page...
最佳答案
像这样更改您的 onBackPressed() 方法:
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
finish();
Intent i=new Intent(getApplicationContext(),MainActivity.class);
startActivity(i);
}
关于android - 后退按钮显示空白屏幕，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31863527/