应用程序在将方位从风景改为人像时崩溃

Question

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
    TextView textView=findViewById(R.id.logotext);
    int unicode=0x1F4A1;
    String emoji=getEmoji(unicode);
    String Text="Bsc"+emoji+"T";
    textView.setText(Text);

}
public String getEmoji(int uni)
{
    return new String(Character.toChars(uni));
}

Answer 1

根据您的崩溃日志：

com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) Caused by: 
java.lang.NullPointerException: Attempt to invoke virtual method 'void 
android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference at 
com.studenthelper.bscit.MainActivity.onCreate(MainActivity.java:20) 

这意味着您的textView

TextView textView=findViewById(R.id.logotext);

在布局r.layout.activity_main中找不到，因此当您尝试textview.settext（Text）；时，它实际上为null并发生异常。

所以，我建议

1. 验证textVIew Id在布局中是否相同？和
2. 设置getWindow（）。setFlags(windowmanager.layoutParams.flag_fullscreen，windowmanager.layoutParams.flag_fullscreen)；在SetContentView(r.layout.activity_main)之前；

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); 
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_main);
    TextView textView=findViewById(R.id.logotext);
    int unicode=0x1F4A1;
    String emoji=getEmoji(unicode);
    String Text="Bsc"+emoji+"T";
    textView.setText(Text);

}