Androidstudio编译的apk一运行就显示停止运行

是顺序有错误引起的。修改两个地方：（1）将以下三句：private Button b1 = (Button)findViewById(R.id.buttonTop);private Button b2 = (Button)findViewById(R.id.buttonBottom);private TextView t = (TextView)findViewById(R.id.storyTextView);修改为：private Button b1;private Button b2;private TextView t;（2）在语句：setContentView(R.layout.activity_main); 的后面，增加以下三个语句：b1 = (Button)findViewById(R.id.buttonTop);b2 = (Button)findViewById(R.id.buttonBottom);t = (TextView)findViewById(R.id.storyTextView);